11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * mm/mmap.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Written by obz. 51da177e4SLinus Torvalds * 6046c6884SAlan Cox * Address space accounting code <alan@lxorguk.ukuu.org.uk> 71da177e4SLinus Torvalds */ 81da177e4SLinus Torvalds 91da177e4SLinus Torvalds #include <linux/slab.h> 104af3c9ccSAlexey Dobriyan #include <linux/backing-dev.h> 111da177e4SLinus Torvalds #include <linux/mm.h> 121da177e4SLinus Torvalds #include <linux/shm.h> 131da177e4SLinus Torvalds #include <linux/mman.h> 141da177e4SLinus Torvalds #include <linux/pagemap.h> 151da177e4SLinus Torvalds #include <linux/swap.h> 161da177e4SLinus Torvalds #include <linux/syscalls.h> 17c59ede7bSRandy.Dunlap #include <linux/capability.h> 181da177e4SLinus Torvalds #include <linux/init.h> 191da177e4SLinus Torvalds #include <linux/file.h> 201da177e4SLinus Torvalds #include <linux/fs.h> 211da177e4SLinus Torvalds #include <linux/personality.h> 221da177e4SLinus Torvalds #include <linux/security.h> 231da177e4SLinus Torvalds #include <linux/hugetlb.h> 241da177e4SLinus Torvalds #include <linux/profile.h> 25b95f1b31SPaul Gortmaker #include <linux/export.h> 261da177e4SLinus Torvalds #include <linux/mount.h> 271da177e4SLinus Torvalds #include <linux/mempolicy.h> 281da177e4SLinus Torvalds #include <linux/rmap.h> 29cddb8a5cSAndrea Arcangeli #include <linux/mmu_notifier.h> 30cdd6c482SIngo Molnar #include <linux/perf_event.h> 31120a795dSAl Viro #include <linux/audit.h> 32b15d00b6SAndrea Arcangeli #include <linux/khugepaged.h> 332b144498SSrikar Dronamraju #include <linux/uprobes.h> 34d3737187SMichel Lespinasse #include <linux/rbtree_augmented.h> 35cf4aebc2SClark Williams #include <linux/sched/sysctl.h> 361da177e4SLinus Torvalds 371da177e4SLinus Torvalds #include <asm/uaccess.h> 381da177e4SLinus Torvalds #include <asm/cacheflush.h> 391da177e4SLinus Torvalds #include <asm/tlb.h> 40d6dd61c8SJeremy Fitzhardinge #include <asm/mmu_context.h> 411da177e4SLinus Torvalds 4242b77728SJan Beulich #include "internal.h" 4342b77728SJan Beulich 443a459756SKirill Korotaev #ifndef arch_mmap_check 453a459756SKirill Korotaev #define arch_mmap_check(addr, len, flags) (0) 463a459756SKirill Korotaev #endif 473a459756SKirill Korotaev 4808e7d9b5SMartin Schwidefsky #ifndef arch_rebalance_pgtables 4908e7d9b5SMartin Schwidefsky #define arch_rebalance_pgtables(addr, len) (addr) 5008e7d9b5SMartin Schwidefsky #endif 5108e7d9b5SMartin Schwidefsky 52e0da382cSHugh Dickins static void unmap_region(struct mm_struct *mm, 53e0da382cSHugh Dickins struct vm_area_struct *vma, struct vm_area_struct *prev, 54e0da382cSHugh Dickins unsigned long start, unsigned long end); 55e0da382cSHugh Dickins 561da177e4SLinus Torvalds /* description of effects of mapping type and prot in current implementation. 571da177e4SLinus Torvalds * this is due to the limited x86 page protection hardware. The expected 581da177e4SLinus Torvalds * behavior is in parens: 591da177e4SLinus Torvalds * 601da177e4SLinus Torvalds * map_type prot 611da177e4SLinus Torvalds * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC 621da177e4SLinus Torvalds * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes 631da177e4SLinus Torvalds * w: (no) no w: (no) no w: (yes) yes w: (no) no 641da177e4SLinus Torvalds * x: (no) no x: (no) yes x: (no) yes x: (yes) yes 651da177e4SLinus Torvalds * 661da177e4SLinus Torvalds * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes 671da177e4SLinus Torvalds * w: (no) no w: (no) no w: (copy) copy w: (no) no 681da177e4SLinus Torvalds * x: (no) no x: (no) yes x: (no) yes x: (yes) yes 691da177e4SLinus Torvalds * 701da177e4SLinus Torvalds */ 711da177e4SLinus Torvalds pgprot_t protection_map[16] = { 721da177e4SLinus Torvalds __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, 731da177e4SLinus Torvalds __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 741da177e4SLinus Torvalds }; 751da177e4SLinus Torvalds 76804af2cfSHugh Dickins pgprot_t vm_get_page_prot(unsigned long vm_flags) 77804af2cfSHugh Dickins { 78b845f313SDave Kleikamp return __pgprot(pgprot_val(protection_map[vm_flags & 79b845f313SDave Kleikamp (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | 80b845f313SDave Kleikamp pgprot_val(arch_vm_get_page_prot(vm_flags))); 81804af2cfSHugh Dickins } 82804af2cfSHugh Dickins EXPORT_SYMBOL(vm_get_page_prot); 83804af2cfSHugh Dickins 8434679d7eSShaohua Li int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */ 8534679d7eSShaohua Li int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */ 86c3d8c141SChristoph Lameter int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; 8734679d7eSShaohua Li /* 8834679d7eSShaohua Li * Make sure vm_committed_as in one cacheline and not cacheline shared with 8934679d7eSShaohua Li * other variables. It can be updated by several CPUs frequently. 9034679d7eSShaohua Li */ 9134679d7eSShaohua Li struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; 921da177e4SLinus Torvalds 931da177e4SLinus Torvalds /* 94997071bcSK. Y. Srinivasan * The global memory commitment made in the system can be a metric 95997071bcSK. Y. Srinivasan * that can be used to drive ballooning decisions when Linux is hosted 96997071bcSK. Y. Srinivasan * as a guest. On Hyper-V, the host implements a policy engine for dynamically 97997071bcSK. Y. Srinivasan * balancing memory across competing virtual machines that are hosted. 98997071bcSK. Y. Srinivasan * Several metrics drive this policy engine including the guest reported 99997071bcSK. Y. Srinivasan * memory commitment. 100997071bcSK. Y. Srinivasan */ 101997071bcSK. Y. Srinivasan unsigned long vm_memory_committed(void) 102997071bcSK. Y. Srinivasan { 103997071bcSK. Y. Srinivasan return percpu_counter_read_positive(&vm_committed_as); 104997071bcSK. Y. Srinivasan } 105997071bcSK. Y. Srinivasan EXPORT_SYMBOL_GPL(vm_memory_committed); 106997071bcSK. Y. Srinivasan 107997071bcSK. Y. Srinivasan /* 1081da177e4SLinus Torvalds * Check that a process has enough memory to allocate a new virtual 1091da177e4SLinus Torvalds * mapping. 0 means there is enough memory for the allocation to 1101da177e4SLinus Torvalds * succeed and -ENOMEM implies there is not. 1111da177e4SLinus Torvalds * 1121da177e4SLinus Torvalds * We currently support three overcommit policies, which are set via the 1131da177e4SLinus Torvalds * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting 1141da177e4SLinus Torvalds * 1151da177e4SLinus Torvalds * Strict overcommit modes added 2002 Feb 26 by Alan Cox. 1161da177e4SLinus Torvalds * Additional code 2002 Jul 20 by Robert Love. 1171da177e4SLinus Torvalds * 1181da177e4SLinus Torvalds * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. 1191da177e4SLinus Torvalds * 1201da177e4SLinus Torvalds * Note this is a helper function intended to be used by LSMs which 1211da177e4SLinus Torvalds * wish to use this logic. 1221da177e4SLinus Torvalds */ 12334b4e4aaSAlan Cox int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) 1241da177e4SLinus Torvalds { 1251da177e4SLinus Torvalds unsigned long free, allowed; 1261da177e4SLinus Torvalds 1271da177e4SLinus Torvalds vm_acct_memory(pages); 1281da177e4SLinus Torvalds 1291da177e4SLinus Torvalds /* 1301da177e4SLinus Torvalds * Sometimes we want to use more memory than we have 1311da177e4SLinus Torvalds */ 1321da177e4SLinus Torvalds if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) 1331da177e4SLinus Torvalds return 0; 1341da177e4SLinus Torvalds 1351da177e4SLinus Torvalds if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { 136c15bef30SDmitry Fink free = global_page_state(NR_FREE_PAGES); 137c15bef30SDmitry Fink free += global_page_state(NR_FILE_PAGES); 1381da177e4SLinus Torvalds 139c15bef30SDmitry Fink /* 140c15bef30SDmitry Fink * shmem pages shouldn't be counted as free in this 141c15bef30SDmitry Fink * case, they can't be purged, only swapped out, and 142c15bef30SDmitry Fink * that won't affect the overall amount of available 143c15bef30SDmitry Fink * memory in the system. 144c15bef30SDmitry Fink */ 145c15bef30SDmitry Fink free -= global_page_state(NR_SHMEM); 146c15bef30SDmitry Fink 1471da177e4SLinus Torvalds free += nr_swap_pages; 1481da177e4SLinus Torvalds 1491da177e4SLinus Torvalds /* 1501da177e4SLinus Torvalds * Any slabs which are created with the 1511da177e4SLinus Torvalds * SLAB_RECLAIM_ACCOUNT flag claim to have contents 1521da177e4SLinus Torvalds * which are reclaimable, under pressure. The dentry 1531da177e4SLinus Torvalds * cache and most inode caches should fall into this 1541da177e4SLinus Torvalds */ 155972d1a7bSChristoph Lameter free += global_page_state(NR_SLAB_RECLAIMABLE); 1561da177e4SLinus Torvalds 1571da177e4SLinus Torvalds /* 158c15bef30SDmitry Fink * Leave reserved pages. The pages are not for anonymous pages. 159c15bef30SDmitry Fink */ 160c15bef30SDmitry Fink if (free <= totalreserve_pages) 161c15bef30SDmitry Fink goto error; 162c15bef30SDmitry Fink else 163c15bef30SDmitry Fink free -= totalreserve_pages; 164c15bef30SDmitry Fink 165c15bef30SDmitry Fink /* 1661da177e4SLinus Torvalds * Leave the last 3% for root 1671da177e4SLinus Torvalds */ 1681da177e4SLinus Torvalds if (!cap_sys_admin) 1691da177e4SLinus Torvalds free -= free / 32; 1701da177e4SLinus Torvalds 1711da177e4SLinus Torvalds if (free > pages) 1721da177e4SLinus Torvalds return 0; 1731da177e4SLinus Torvalds 1746d9f7839SHideo AOKI goto error; 1751da177e4SLinus Torvalds } 1761da177e4SLinus Torvalds 1771da177e4SLinus Torvalds allowed = (totalram_pages - hugetlb_total_pages()) 1781da177e4SLinus Torvalds * sysctl_overcommit_ratio / 100; 1791da177e4SLinus Torvalds /* 1801da177e4SLinus Torvalds * Leave the last 3% for root 1811da177e4SLinus Torvalds */ 1821da177e4SLinus Torvalds if (!cap_sys_admin) 1831da177e4SLinus Torvalds allowed -= allowed / 32; 1841da177e4SLinus Torvalds allowed += total_swap_pages; 1851da177e4SLinus Torvalds 1861da177e4SLinus Torvalds /* Don't let a single process grow too big: 1871da177e4SLinus Torvalds leave 3% of the size of this process for other processes */ 188731572d3SAlan Cox if (mm) 18934b4e4aaSAlan Cox allowed -= mm->total_vm / 32; 1901da177e4SLinus Torvalds 19100a62ce9SKOSAKI Motohiro if (percpu_counter_read_positive(&vm_committed_as) < allowed) 1921da177e4SLinus Torvalds return 0; 1936d9f7839SHideo AOKI error: 1941da177e4SLinus Torvalds vm_unacct_memory(pages); 1951da177e4SLinus Torvalds 1961da177e4SLinus Torvalds return -ENOMEM; 1971da177e4SLinus Torvalds } 1981da177e4SLinus Torvalds 1991da177e4SLinus Torvalds /* 2003d48ae45SPeter Zijlstra * Requires inode->i_mapping->i_mmap_mutex 2011da177e4SLinus Torvalds */ 2021da177e4SLinus Torvalds static void __remove_shared_vm_struct(struct vm_area_struct *vma, 2031da177e4SLinus Torvalds struct file *file, struct address_space *mapping) 2041da177e4SLinus Torvalds { 2051da177e4SLinus Torvalds if (vma->vm_flags & VM_DENYWRITE) 206d3ac7f89SJosef "Jeff" Sipek atomic_inc(&file->f_path.dentry->d_inode->i_writecount); 2071da177e4SLinus Torvalds if (vma->vm_flags & VM_SHARED) 2081da177e4SLinus Torvalds mapping->i_mmap_writable--; 2091da177e4SLinus Torvalds 2101da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 2111da177e4SLinus Torvalds if (unlikely(vma->vm_flags & VM_NONLINEAR)) 2126b2dbba8SMichel Lespinasse list_del_init(&vma->shared.nonlinear); 2131da177e4SLinus Torvalds else 2146b2dbba8SMichel Lespinasse vma_interval_tree_remove(vma, &mapping->i_mmap); 2151da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 2161da177e4SLinus Torvalds } 2171da177e4SLinus Torvalds 2181da177e4SLinus Torvalds /* 2196b2dbba8SMichel Lespinasse * Unlink a file-based vm structure from its interval tree, to hide 220a8fb5618SHugh Dickins * vma from rmap and vmtruncate before freeing its page tables. 2211da177e4SLinus Torvalds */ 222a8fb5618SHugh Dickins void unlink_file_vma(struct vm_area_struct *vma) 2231da177e4SLinus Torvalds { 2241da177e4SLinus Torvalds struct file *file = vma->vm_file; 2251da177e4SLinus Torvalds 2261da177e4SLinus Torvalds if (file) { 2271da177e4SLinus Torvalds struct address_space *mapping = file->f_mapping; 2283d48ae45SPeter Zijlstra mutex_lock(&mapping->i_mmap_mutex); 2291da177e4SLinus Torvalds __remove_shared_vm_struct(vma, file, mapping); 2303d48ae45SPeter Zijlstra mutex_unlock(&mapping->i_mmap_mutex); 2311da177e4SLinus Torvalds } 232a8fb5618SHugh Dickins } 233a8fb5618SHugh Dickins 234a8fb5618SHugh Dickins /* 235a8fb5618SHugh Dickins * Close a vm structure and free it, returning the next. 236a8fb5618SHugh Dickins */ 237a8fb5618SHugh Dickins static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) 238a8fb5618SHugh Dickins { 239a8fb5618SHugh Dickins struct vm_area_struct *next = vma->vm_next; 240a8fb5618SHugh Dickins 241a8fb5618SHugh Dickins might_sleep(); 2421da177e4SLinus Torvalds if (vma->vm_ops && vma->vm_ops->close) 2431da177e4SLinus Torvalds vma->vm_ops->close(vma); 244e9714acfSKonstantin Khlebnikov if (vma->vm_file) 245a8fb5618SHugh Dickins fput(vma->vm_file); 246f0be3d32SLee Schermerhorn mpol_put(vma_policy(vma)); 2471da177e4SLinus Torvalds kmem_cache_free(vm_area_cachep, vma); 248a8fb5618SHugh Dickins return next; 2491da177e4SLinus Torvalds } 2501da177e4SLinus Torvalds 251e4eb1ff6SLinus Torvalds static unsigned long do_brk(unsigned long addr, unsigned long len); 252e4eb1ff6SLinus Torvalds 2536a6160a7SHeiko Carstens SYSCALL_DEFINE1(brk, unsigned long, brk) 2541da177e4SLinus Torvalds { 2551da177e4SLinus Torvalds unsigned long rlim, retval; 2561da177e4SLinus Torvalds unsigned long newbrk, oldbrk; 2571da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 258a5b4592cSJiri Kosina unsigned long min_brk; 2591da177e4SLinus Torvalds 2601da177e4SLinus Torvalds down_write(&mm->mmap_sem); 2611da177e4SLinus Torvalds 262a5b4592cSJiri Kosina #ifdef CONFIG_COMPAT_BRK 2635520e894SJiri Kosina /* 2645520e894SJiri Kosina * CONFIG_COMPAT_BRK can still be overridden by setting 2655520e894SJiri Kosina * randomize_va_space to 2, which will still cause mm->start_brk 2665520e894SJiri Kosina * to be arbitrarily shifted 2675520e894SJiri Kosina */ 2684471a675SJiri Kosina if (current->brk_randomized) 2695520e894SJiri Kosina min_brk = mm->start_brk; 2705520e894SJiri Kosina else 2715520e894SJiri Kosina min_brk = mm->end_data; 272a5b4592cSJiri Kosina #else 273a5b4592cSJiri Kosina min_brk = mm->start_brk; 274a5b4592cSJiri Kosina #endif 275a5b4592cSJiri Kosina if (brk < min_brk) 2761da177e4SLinus Torvalds goto out; 2771e624196SRam Gupta 2781e624196SRam Gupta /* 2791e624196SRam Gupta * Check against rlimit here. If this check is done later after the test 2801e624196SRam Gupta * of oldbrk with newbrk then it can escape the test and let the data 2811e624196SRam Gupta * segment grow beyond its set limit the in case where the limit is 2821e624196SRam Gupta * not page aligned -Ram Gupta 2831e624196SRam Gupta */ 28459e99e5bSJiri Slaby rlim = rlimit(RLIMIT_DATA); 285c1d171a0SJiri Kosina if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + 286c1d171a0SJiri Kosina (mm->end_data - mm->start_data) > rlim) 2871e624196SRam Gupta goto out; 2881e624196SRam Gupta 2891da177e4SLinus Torvalds newbrk = PAGE_ALIGN(brk); 2901da177e4SLinus Torvalds oldbrk = PAGE_ALIGN(mm->brk); 2911da177e4SLinus Torvalds if (oldbrk == newbrk) 2921da177e4SLinus Torvalds goto set_brk; 2931da177e4SLinus Torvalds 2941da177e4SLinus Torvalds /* Always allow shrinking brk. */ 2951da177e4SLinus Torvalds if (brk <= mm->brk) { 2961da177e4SLinus Torvalds if (!do_munmap(mm, newbrk, oldbrk-newbrk)) 2971da177e4SLinus Torvalds goto set_brk; 2981da177e4SLinus Torvalds goto out; 2991da177e4SLinus Torvalds } 3001da177e4SLinus Torvalds 3011da177e4SLinus Torvalds /* Check against existing mmap mappings. */ 3021da177e4SLinus Torvalds if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) 3031da177e4SLinus Torvalds goto out; 3041da177e4SLinus Torvalds 3051da177e4SLinus Torvalds /* Ok, looks good - let it rip. */ 3061da177e4SLinus Torvalds if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) 3071da177e4SLinus Torvalds goto out; 3081da177e4SLinus Torvalds set_brk: 3091da177e4SLinus Torvalds mm->brk = brk; 3101da177e4SLinus Torvalds out: 3111da177e4SLinus Torvalds retval = mm->brk; 3121da177e4SLinus Torvalds up_write(&mm->mmap_sem); 3131da177e4SLinus Torvalds return retval; 3141da177e4SLinus Torvalds } 3151da177e4SLinus Torvalds 316d3737187SMichel Lespinasse static long vma_compute_subtree_gap(struct vm_area_struct *vma) 317d3737187SMichel Lespinasse { 318d3737187SMichel Lespinasse unsigned long max, subtree_gap; 319d3737187SMichel Lespinasse max = vma->vm_start; 320d3737187SMichel Lespinasse if (vma->vm_prev) 321d3737187SMichel Lespinasse max -= vma->vm_prev->vm_end; 322d3737187SMichel Lespinasse if (vma->vm_rb.rb_left) { 323d3737187SMichel Lespinasse subtree_gap = rb_entry(vma->vm_rb.rb_left, 324d3737187SMichel Lespinasse struct vm_area_struct, vm_rb)->rb_subtree_gap; 325d3737187SMichel Lespinasse if (subtree_gap > max) 326d3737187SMichel Lespinasse max = subtree_gap; 327d3737187SMichel Lespinasse } 328d3737187SMichel Lespinasse if (vma->vm_rb.rb_right) { 329d3737187SMichel Lespinasse subtree_gap = rb_entry(vma->vm_rb.rb_right, 330d3737187SMichel Lespinasse struct vm_area_struct, vm_rb)->rb_subtree_gap; 331d3737187SMichel Lespinasse if (subtree_gap > max) 332d3737187SMichel Lespinasse max = subtree_gap; 333d3737187SMichel Lespinasse } 334d3737187SMichel Lespinasse return max; 335d3737187SMichel Lespinasse } 336d3737187SMichel Lespinasse 337ed8ea815SMichel Lespinasse #ifdef CONFIG_DEBUG_VM_RB 3381da177e4SLinus Torvalds static int browse_rb(struct rb_root *root) 3391da177e4SLinus Torvalds { 3405a0768f6SMichel Lespinasse int i = 0, j, bug = 0; 3411da177e4SLinus Torvalds struct rb_node *nd, *pn = NULL; 3421da177e4SLinus Torvalds unsigned long prev = 0, pend = 0; 3431da177e4SLinus Torvalds 3441da177e4SLinus Torvalds for (nd = rb_first(root); nd; nd = rb_next(nd)) { 3451da177e4SLinus Torvalds struct vm_area_struct *vma; 3461da177e4SLinus Torvalds vma = rb_entry(nd, struct vm_area_struct, vm_rb); 3475a0768f6SMichel Lespinasse if (vma->vm_start < prev) { 3485a0768f6SMichel Lespinasse printk("vm_start %lx prev %lx\n", vma->vm_start, prev); 3495a0768f6SMichel Lespinasse bug = 1; 3505a0768f6SMichel Lespinasse } 3515a0768f6SMichel Lespinasse if (vma->vm_start < pend) { 3521da177e4SLinus Torvalds printk("vm_start %lx pend %lx\n", vma->vm_start, pend); 3535a0768f6SMichel Lespinasse bug = 1; 3545a0768f6SMichel Lespinasse } 3555a0768f6SMichel Lespinasse if (vma->vm_start > vma->vm_end) { 3565a0768f6SMichel Lespinasse printk("vm_end %lx < vm_start %lx\n", 3575a0768f6SMichel Lespinasse vma->vm_end, vma->vm_start); 3585a0768f6SMichel Lespinasse bug = 1; 3595a0768f6SMichel Lespinasse } 3605a0768f6SMichel Lespinasse if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) { 3615a0768f6SMichel Lespinasse printk("free gap %lx, correct %lx\n", 3625a0768f6SMichel Lespinasse vma->rb_subtree_gap, 3635a0768f6SMichel Lespinasse vma_compute_subtree_gap(vma)); 3645a0768f6SMichel Lespinasse bug = 1; 3655a0768f6SMichel Lespinasse } 3661da177e4SLinus Torvalds i++; 3671da177e4SLinus Torvalds pn = nd; 368d1af65d1SDavid Miller prev = vma->vm_start; 369d1af65d1SDavid Miller pend = vma->vm_end; 3701da177e4SLinus Torvalds } 3711da177e4SLinus Torvalds j = 0; 3725a0768f6SMichel Lespinasse for (nd = pn; nd; nd = rb_prev(nd)) 3731da177e4SLinus Torvalds j++; 3745a0768f6SMichel Lespinasse if (i != j) { 3755a0768f6SMichel Lespinasse printk("backwards %d, forwards %d\n", j, i); 3765a0768f6SMichel Lespinasse bug = 1; 3771da177e4SLinus Torvalds } 3785a0768f6SMichel Lespinasse return bug ? -1 : i; 3791da177e4SLinus Torvalds } 3801da177e4SLinus Torvalds 381d3737187SMichel Lespinasse static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore) 382d3737187SMichel Lespinasse { 383d3737187SMichel Lespinasse struct rb_node *nd; 384d3737187SMichel Lespinasse 385d3737187SMichel Lespinasse for (nd = rb_first(root); nd; nd = rb_next(nd)) { 386d3737187SMichel Lespinasse struct vm_area_struct *vma; 387d3737187SMichel Lespinasse vma = rb_entry(nd, struct vm_area_struct, vm_rb); 388d3737187SMichel Lespinasse BUG_ON(vma != ignore && 389d3737187SMichel Lespinasse vma->rb_subtree_gap != vma_compute_subtree_gap(vma)); 390d3737187SMichel Lespinasse } 3911da177e4SLinus Torvalds } 3921da177e4SLinus Torvalds 3931da177e4SLinus Torvalds void validate_mm(struct mm_struct *mm) 3941da177e4SLinus Torvalds { 3951da177e4SLinus Torvalds int bug = 0; 3961da177e4SLinus Torvalds int i = 0; 3975a0768f6SMichel Lespinasse unsigned long highest_address = 0; 398ed8ea815SMichel Lespinasse struct vm_area_struct *vma = mm->mmap; 399ed8ea815SMichel Lespinasse while (vma) { 400ed8ea815SMichel Lespinasse struct anon_vma_chain *avc; 40163c3b902SMichel Lespinasse vma_lock_anon_vma(vma); 402ed8ea815SMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 403ed8ea815SMichel Lespinasse anon_vma_interval_tree_verify(avc); 40463c3b902SMichel Lespinasse vma_unlock_anon_vma(vma); 4055a0768f6SMichel Lespinasse highest_address = vma->vm_end; 406ed8ea815SMichel Lespinasse vma = vma->vm_next; 4071da177e4SLinus Torvalds i++; 4081da177e4SLinus Torvalds } 4095a0768f6SMichel Lespinasse if (i != mm->map_count) { 4105a0768f6SMichel Lespinasse printk("map_count %d vm_next %d\n", mm->map_count, i); 4115a0768f6SMichel Lespinasse bug = 1; 4125a0768f6SMichel Lespinasse } 4135a0768f6SMichel Lespinasse if (highest_address != mm->highest_vm_end) { 4145a0768f6SMichel Lespinasse printk("mm->highest_vm_end %lx, found %lx\n", 4155a0768f6SMichel Lespinasse mm->highest_vm_end, highest_address); 4165a0768f6SMichel Lespinasse bug = 1; 4175a0768f6SMichel Lespinasse } 4181da177e4SLinus Torvalds i = browse_rb(&mm->mm_rb); 4195a0768f6SMichel Lespinasse if (i != mm->map_count) { 4205a0768f6SMichel Lespinasse printk("map_count %d rb %d\n", mm->map_count, i); 4215a0768f6SMichel Lespinasse bug = 1; 4225a0768f6SMichel Lespinasse } 42346a350efSEric Sesterhenn BUG_ON(bug); 4241da177e4SLinus Torvalds } 4251da177e4SLinus Torvalds #else 426d3737187SMichel Lespinasse #define validate_mm_rb(root, ignore) do { } while (0) 4271da177e4SLinus Torvalds #define validate_mm(mm) do { } while (0) 4281da177e4SLinus Torvalds #endif 4291da177e4SLinus Torvalds 430d3737187SMichel Lespinasse RB_DECLARE_CALLBACKS(static, vma_gap_callbacks, struct vm_area_struct, vm_rb, 431d3737187SMichel Lespinasse unsigned long, rb_subtree_gap, vma_compute_subtree_gap) 432d3737187SMichel Lespinasse 433d3737187SMichel Lespinasse /* 434d3737187SMichel Lespinasse * Update augmented rbtree rb_subtree_gap values after vma->vm_start or 435d3737187SMichel Lespinasse * vma->vm_prev->vm_end values changed, without modifying the vma's position 436d3737187SMichel Lespinasse * in the rbtree. 437d3737187SMichel Lespinasse */ 438d3737187SMichel Lespinasse static void vma_gap_update(struct vm_area_struct *vma) 439d3737187SMichel Lespinasse { 440d3737187SMichel Lespinasse /* 441d3737187SMichel Lespinasse * As it turns out, RB_DECLARE_CALLBACKS() already created a callback 442d3737187SMichel Lespinasse * function that does exacltly what we want. 443d3737187SMichel Lespinasse */ 444d3737187SMichel Lespinasse vma_gap_callbacks_propagate(&vma->vm_rb, NULL); 445d3737187SMichel Lespinasse } 446d3737187SMichel Lespinasse 447d3737187SMichel Lespinasse static inline void vma_rb_insert(struct vm_area_struct *vma, 448d3737187SMichel Lespinasse struct rb_root *root) 449d3737187SMichel Lespinasse { 450d3737187SMichel Lespinasse /* All rb_subtree_gap values must be consistent prior to insertion */ 451d3737187SMichel Lespinasse validate_mm_rb(root, NULL); 452d3737187SMichel Lespinasse 453d3737187SMichel Lespinasse rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks); 454d3737187SMichel Lespinasse } 455d3737187SMichel Lespinasse 456d3737187SMichel Lespinasse static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root) 457d3737187SMichel Lespinasse { 458d3737187SMichel Lespinasse /* 459d3737187SMichel Lespinasse * All rb_subtree_gap values must be consistent prior to erase, 460d3737187SMichel Lespinasse * with the possible exception of the vma being erased. 461d3737187SMichel Lespinasse */ 462d3737187SMichel Lespinasse validate_mm_rb(root, vma); 463d3737187SMichel Lespinasse 464d3737187SMichel Lespinasse /* 465d3737187SMichel Lespinasse * Note rb_erase_augmented is a fairly large inline function, 466d3737187SMichel Lespinasse * so make sure we instantiate it only once with our desired 467d3737187SMichel Lespinasse * augmented rbtree callbacks. 468d3737187SMichel Lespinasse */ 469d3737187SMichel Lespinasse rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks); 470d3737187SMichel Lespinasse } 471d3737187SMichel Lespinasse 472bf181b9fSMichel Lespinasse /* 473bf181b9fSMichel Lespinasse * vma has some anon_vma assigned, and is already inserted on that 474bf181b9fSMichel Lespinasse * anon_vma's interval trees. 475bf181b9fSMichel Lespinasse * 476bf181b9fSMichel Lespinasse * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the 477bf181b9fSMichel Lespinasse * vma must be removed from the anon_vma's interval trees using 478bf181b9fSMichel Lespinasse * anon_vma_interval_tree_pre_update_vma(). 479bf181b9fSMichel Lespinasse * 480bf181b9fSMichel Lespinasse * After the update, the vma will be reinserted using 481bf181b9fSMichel Lespinasse * anon_vma_interval_tree_post_update_vma(). 482bf181b9fSMichel Lespinasse * 483bf181b9fSMichel Lespinasse * The entire update must be protected by exclusive mmap_sem and by 484bf181b9fSMichel Lespinasse * the root anon_vma's mutex. 485bf181b9fSMichel Lespinasse */ 486bf181b9fSMichel Lespinasse static inline void 487bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma) 488bf181b9fSMichel Lespinasse { 489bf181b9fSMichel Lespinasse struct anon_vma_chain *avc; 490bf181b9fSMichel Lespinasse 491bf181b9fSMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 492bf181b9fSMichel Lespinasse anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root); 493bf181b9fSMichel Lespinasse } 494bf181b9fSMichel Lespinasse 495bf181b9fSMichel Lespinasse static inline void 496bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma) 497bf181b9fSMichel Lespinasse { 498bf181b9fSMichel Lespinasse struct anon_vma_chain *avc; 499bf181b9fSMichel Lespinasse 500bf181b9fSMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 501bf181b9fSMichel Lespinasse anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root); 502bf181b9fSMichel Lespinasse } 503bf181b9fSMichel Lespinasse 5046597d783SHugh Dickins static int find_vma_links(struct mm_struct *mm, unsigned long addr, 5056597d783SHugh Dickins unsigned long end, struct vm_area_struct **pprev, 5066597d783SHugh Dickins struct rb_node ***rb_link, struct rb_node **rb_parent) 5071da177e4SLinus Torvalds { 5081da177e4SLinus Torvalds struct rb_node **__rb_link, *__rb_parent, *rb_prev; 5091da177e4SLinus Torvalds 5101da177e4SLinus Torvalds __rb_link = &mm->mm_rb.rb_node; 5111da177e4SLinus Torvalds rb_prev = __rb_parent = NULL; 5121da177e4SLinus Torvalds 5131da177e4SLinus Torvalds while (*__rb_link) { 5141da177e4SLinus Torvalds struct vm_area_struct *vma_tmp; 5151da177e4SLinus Torvalds 5161da177e4SLinus Torvalds __rb_parent = *__rb_link; 5171da177e4SLinus Torvalds vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); 5181da177e4SLinus Torvalds 5191da177e4SLinus Torvalds if (vma_tmp->vm_end > addr) { 5206597d783SHugh Dickins /* Fail if an existing vma overlaps the area */ 5216597d783SHugh Dickins if (vma_tmp->vm_start < end) 5226597d783SHugh Dickins return -ENOMEM; 5231da177e4SLinus Torvalds __rb_link = &__rb_parent->rb_left; 5241da177e4SLinus Torvalds } else { 5251da177e4SLinus Torvalds rb_prev = __rb_parent; 5261da177e4SLinus Torvalds __rb_link = &__rb_parent->rb_right; 5271da177e4SLinus Torvalds } 5281da177e4SLinus Torvalds } 5291da177e4SLinus Torvalds 5301da177e4SLinus Torvalds *pprev = NULL; 5311da177e4SLinus Torvalds if (rb_prev) 5321da177e4SLinus Torvalds *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); 5331da177e4SLinus Torvalds *rb_link = __rb_link; 5341da177e4SLinus Torvalds *rb_parent = __rb_parent; 5356597d783SHugh Dickins return 0; 5361da177e4SLinus Torvalds } 5371da177e4SLinus Torvalds 5381da177e4SLinus Torvalds void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, 5391da177e4SLinus Torvalds struct rb_node **rb_link, struct rb_node *rb_parent) 5401da177e4SLinus Torvalds { 541d3737187SMichel Lespinasse /* Update tracking information for the gap following the new vma. */ 542d3737187SMichel Lespinasse if (vma->vm_next) 543d3737187SMichel Lespinasse vma_gap_update(vma->vm_next); 544d3737187SMichel Lespinasse else 545d3737187SMichel Lespinasse mm->highest_vm_end = vma->vm_end; 546d3737187SMichel Lespinasse 547d3737187SMichel Lespinasse /* 548d3737187SMichel Lespinasse * vma->vm_prev wasn't known when we followed the rbtree to find the 549d3737187SMichel Lespinasse * correct insertion point for that vma. As a result, we could not 550d3737187SMichel Lespinasse * update the vma vm_rb parents rb_subtree_gap values on the way down. 551d3737187SMichel Lespinasse * So, we first insert the vma with a zero rb_subtree_gap value 552d3737187SMichel Lespinasse * (to be consistent with what we did on the way down), and then 553d3737187SMichel Lespinasse * immediately update the gap to the correct value. Finally we 554d3737187SMichel Lespinasse * rebalance the rbtree after all augmented values have been set. 555d3737187SMichel Lespinasse */ 5561da177e4SLinus Torvalds rb_link_node(&vma->vm_rb, rb_parent, rb_link); 557d3737187SMichel Lespinasse vma->rb_subtree_gap = 0; 558d3737187SMichel Lespinasse vma_gap_update(vma); 559d3737187SMichel Lespinasse vma_rb_insert(vma, &mm->mm_rb); 5601da177e4SLinus Torvalds } 5611da177e4SLinus Torvalds 562cb8f488cSDenys Vlasenko static void __vma_link_file(struct vm_area_struct *vma) 5631da177e4SLinus Torvalds { 5641da177e4SLinus Torvalds struct file *file; 5651da177e4SLinus Torvalds 5661da177e4SLinus Torvalds file = vma->vm_file; 5671da177e4SLinus Torvalds if (file) { 5681da177e4SLinus Torvalds struct address_space *mapping = file->f_mapping; 5691da177e4SLinus Torvalds 5701da177e4SLinus Torvalds if (vma->vm_flags & VM_DENYWRITE) 571d3ac7f89SJosef "Jeff" Sipek atomic_dec(&file->f_path.dentry->d_inode->i_writecount); 5721da177e4SLinus Torvalds if (vma->vm_flags & VM_SHARED) 5731da177e4SLinus Torvalds mapping->i_mmap_writable++; 5741da177e4SLinus Torvalds 5751da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 5761da177e4SLinus Torvalds if (unlikely(vma->vm_flags & VM_NONLINEAR)) 5771da177e4SLinus Torvalds vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); 5781da177e4SLinus Torvalds else 5796b2dbba8SMichel Lespinasse vma_interval_tree_insert(vma, &mapping->i_mmap); 5801da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 5811da177e4SLinus Torvalds } 5821da177e4SLinus Torvalds } 5831da177e4SLinus Torvalds 5841da177e4SLinus Torvalds static void 5851da177e4SLinus Torvalds __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, 5861da177e4SLinus Torvalds struct vm_area_struct *prev, struct rb_node **rb_link, 5871da177e4SLinus Torvalds struct rb_node *rb_parent) 5881da177e4SLinus Torvalds { 5891da177e4SLinus Torvalds __vma_link_list(mm, vma, prev, rb_parent); 5901da177e4SLinus Torvalds __vma_link_rb(mm, vma, rb_link, rb_parent); 5911da177e4SLinus Torvalds } 5921da177e4SLinus Torvalds 5931da177e4SLinus Torvalds static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, 5941da177e4SLinus Torvalds struct vm_area_struct *prev, struct rb_node **rb_link, 5951da177e4SLinus Torvalds struct rb_node *rb_parent) 5961da177e4SLinus Torvalds { 5971da177e4SLinus Torvalds struct address_space *mapping = NULL; 5981da177e4SLinus Torvalds 5991da177e4SLinus Torvalds if (vma->vm_file) 6001da177e4SLinus Torvalds mapping = vma->vm_file->f_mapping; 6011da177e4SLinus Torvalds 60297a89413SPeter Zijlstra if (mapping) 6033d48ae45SPeter Zijlstra mutex_lock(&mapping->i_mmap_mutex); 6041da177e4SLinus Torvalds 6051da177e4SLinus Torvalds __vma_link(mm, vma, prev, rb_link, rb_parent); 6061da177e4SLinus Torvalds __vma_link_file(vma); 6071da177e4SLinus Torvalds 6081da177e4SLinus Torvalds if (mapping) 6093d48ae45SPeter Zijlstra mutex_unlock(&mapping->i_mmap_mutex); 6101da177e4SLinus Torvalds 6111da177e4SLinus Torvalds mm->map_count++; 6121da177e4SLinus Torvalds validate_mm(mm); 6131da177e4SLinus Torvalds } 6141da177e4SLinus Torvalds 6151da177e4SLinus Torvalds /* 61688f6b4c3SKautuk Consul * Helper for vma_adjust() in the split_vma insert case: insert a vma into the 6176b2dbba8SMichel Lespinasse * mm's list and rbtree. It has already been inserted into the interval tree. 6181da177e4SLinus Torvalds */ 61948aae425SZhenwenXu static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) 6201da177e4SLinus Torvalds { 6216597d783SHugh Dickins struct vm_area_struct *prev; 6221da177e4SLinus Torvalds struct rb_node **rb_link, *rb_parent; 6231da177e4SLinus Torvalds 6246597d783SHugh Dickins if (find_vma_links(mm, vma->vm_start, vma->vm_end, 6256597d783SHugh Dickins &prev, &rb_link, &rb_parent)) 6266597d783SHugh Dickins BUG(); 6271da177e4SLinus Torvalds __vma_link(mm, vma, prev, rb_link, rb_parent); 6281da177e4SLinus Torvalds mm->map_count++; 6291da177e4SLinus Torvalds } 6301da177e4SLinus Torvalds 6311da177e4SLinus Torvalds static inline void 6321da177e4SLinus Torvalds __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, 6331da177e4SLinus Torvalds struct vm_area_struct *prev) 6341da177e4SLinus Torvalds { 635d3737187SMichel Lespinasse struct vm_area_struct *next; 636297c5eeeSLinus Torvalds 637d3737187SMichel Lespinasse vma_rb_erase(vma, &mm->mm_rb); 638d3737187SMichel Lespinasse prev->vm_next = next = vma->vm_next; 639297c5eeeSLinus Torvalds if (next) 640297c5eeeSLinus Torvalds next->vm_prev = prev; 6411da177e4SLinus Torvalds if (mm->mmap_cache == vma) 6421da177e4SLinus Torvalds mm->mmap_cache = prev; 6431da177e4SLinus Torvalds } 6441da177e4SLinus Torvalds 6451da177e4SLinus Torvalds /* 6461da177e4SLinus Torvalds * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that 6471da177e4SLinus Torvalds * is already present in an i_mmap tree without adjusting the tree. 6481da177e4SLinus Torvalds * The following helper function should be used when such adjustments 6491da177e4SLinus Torvalds * are necessary. The "insert" vma (if any) is to be inserted 6501da177e4SLinus Torvalds * before we drop the necessary locks. 6511da177e4SLinus Torvalds */ 6525beb4930SRik van Riel int vma_adjust(struct vm_area_struct *vma, unsigned long start, 6531da177e4SLinus Torvalds unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert) 6541da177e4SLinus Torvalds { 6551da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 6561da177e4SLinus Torvalds struct vm_area_struct *next = vma->vm_next; 6571da177e4SLinus Torvalds struct vm_area_struct *importer = NULL; 6581da177e4SLinus Torvalds struct address_space *mapping = NULL; 6596b2dbba8SMichel Lespinasse struct rb_root *root = NULL; 660012f1800SRik van Riel struct anon_vma *anon_vma = NULL; 6611da177e4SLinus Torvalds struct file *file = vma->vm_file; 662d3737187SMichel Lespinasse bool start_changed = false, end_changed = false; 6631da177e4SLinus Torvalds long adjust_next = 0; 6641da177e4SLinus Torvalds int remove_next = 0; 6651da177e4SLinus Torvalds 6661da177e4SLinus Torvalds if (next && !insert) { 667287d97acSLinus Torvalds struct vm_area_struct *exporter = NULL; 668287d97acSLinus Torvalds 6691da177e4SLinus Torvalds if (end >= next->vm_end) { 6701da177e4SLinus Torvalds /* 6711da177e4SLinus Torvalds * vma expands, overlapping all the next, and 6721da177e4SLinus Torvalds * perhaps the one after too (mprotect case 6). 6731da177e4SLinus Torvalds */ 6741da177e4SLinus Torvalds again: remove_next = 1 + (end > next->vm_end); 6751da177e4SLinus Torvalds end = next->vm_end; 676287d97acSLinus Torvalds exporter = next; 6771da177e4SLinus Torvalds importer = vma; 6781da177e4SLinus Torvalds } else if (end > next->vm_start) { 6791da177e4SLinus Torvalds /* 6801da177e4SLinus Torvalds * vma expands, overlapping part of the next: 6811da177e4SLinus Torvalds * mprotect case 5 shifting the boundary up. 6821da177e4SLinus Torvalds */ 6831da177e4SLinus Torvalds adjust_next = (end - next->vm_start) >> PAGE_SHIFT; 684287d97acSLinus Torvalds exporter = next; 6851da177e4SLinus Torvalds importer = vma; 6861da177e4SLinus Torvalds } else if (end < vma->vm_end) { 6871da177e4SLinus Torvalds /* 6881da177e4SLinus Torvalds * vma shrinks, and !insert tells it's not 6891da177e4SLinus Torvalds * split_vma inserting another: so it must be 6901da177e4SLinus Torvalds * mprotect case 4 shifting the boundary down. 6911da177e4SLinus Torvalds */ 6921da177e4SLinus Torvalds adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); 693287d97acSLinus Torvalds exporter = vma; 6941da177e4SLinus Torvalds importer = next; 6951da177e4SLinus Torvalds } 6961da177e4SLinus Torvalds 6975beb4930SRik van Riel /* 6985beb4930SRik van Riel * Easily overlooked: when mprotect shifts the boundary, 6995beb4930SRik van Riel * make sure the expanding vma has anon_vma set if the 7005beb4930SRik van Riel * shrinking vma had, to cover any anon pages imported. 7015beb4930SRik van Riel */ 702287d97acSLinus Torvalds if (exporter && exporter->anon_vma && !importer->anon_vma) { 703287d97acSLinus Torvalds if (anon_vma_clone(importer, exporter)) 7045beb4930SRik van Riel return -ENOMEM; 705287d97acSLinus Torvalds importer->anon_vma = exporter->anon_vma; 7065beb4930SRik van Riel } 7075beb4930SRik van Riel } 7085beb4930SRik van Riel 7091da177e4SLinus Torvalds if (file) { 7101da177e4SLinus Torvalds mapping = file->f_mapping; 711682968e0SSrikar Dronamraju if (!(vma->vm_flags & VM_NONLINEAR)) { 7121da177e4SLinus Torvalds root = &mapping->i_mmap; 713cbc91f71SSrikar Dronamraju uprobe_munmap(vma, vma->vm_start, vma->vm_end); 714682968e0SSrikar Dronamraju 715682968e0SSrikar Dronamraju if (adjust_next) 716cbc91f71SSrikar Dronamraju uprobe_munmap(next, next->vm_start, 717cbc91f71SSrikar Dronamraju next->vm_end); 718682968e0SSrikar Dronamraju } 719682968e0SSrikar Dronamraju 7203d48ae45SPeter Zijlstra mutex_lock(&mapping->i_mmap_mutex); 7211da177e4SLinus Torvalds if (insert) { 7221da177e4SLinus Torvalds /* 7236b2dbba8SMichel Lespinasse * Put into interval tree now, so instantiated pages 7241da177e4SLinus Torvalds * are visible to arm/parisc __flush_dcache_page 7251da177e4SLinus Torvalds * throughout; but we cannot insert into address 7261da177e4SLinus Torvalds * space until vma start or end is updated. 7271da177e4SLinus Torvalds */ 7281da177e4SLinus Torvalds __vma_link_file(insert); 7291da177e4SLinus Torvalds } 7301da177e4SLinus Torvalds } 7311da177e4SLinus Torvalds 73294fcc585SAndrea Arcangeli vma_adjust_trans_huge(vma, start, end, adjust_next); 73394fcc585SAndrea Arcangeli 734012f1800SRik van Riel anon_vma = vma->anon_vma; 735bf181b9fSMichel Lespinasse if (!anon_vma && adjust_next) 736bf181b9fSMichel Lespinasse anon_vma = next->anon_vma; 737bf181b9fSMichel Lespinasse if (anon_vma) { 738ca42b26aSMichel Lespinasse VM_BUG_ON(adjust_next && next->anon_vma && 739ca42b26aSMichel Lespinasse anon_vma != next->anon_vma); 7404fc3f1d6SIngo Molnar anon_vma_lock_write(anon_vma); 741bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 742bf181b9fSMichel Lespinasse if (adjust_next) 743bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(next); 744bf181b9fSMichel Lespinasse } 745012f1800SRik van Riel 7461da177e4SLinus Torvalds if (root) { 7471da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 7486b2dbba8SMichel Lespinasse vma_interval_tree_remove(vma, root); 7491da177e4SLinus Torvalds if (adjust_next) 7506b2dbba8SMichel Lespinasse vma_interval_tree_remove(next, root); 7511da177e4SLinus Torvalds } 7521da177e4SLinus Torvalds 753d3737187SMichel Lespinasse if (start != vma->vm_start) { 7541da177e4SLinus Torvalds vma->vm_start = start; 755d3737187SMichel Lespinasse start_changed = true; 756d3737187SMichel Lespinasse } 757d3737187SMichel Lespinasse if (end != vma->vm_end) { 7581da177e4SLinus Torvalds vma->vm_end = end; 759d3737187SMichel Lespinasse end_changed = true; 760d3737187SMichel Lespinasse } 7611da177e4SLinus Torvalds vma->vm_pgoff = pgoff; 7621da177e4SLinus Torvalds if (adjust_next) { 7631da177e4SLinus Torvalds next->vm_start += adjust_next << PAGE_SHIFT; 7641da177e4SLinus Torvalds next->vm_pgoff += adjust_next; 7651da177e4SLinus Torvalds } 7661da177e4SLinus Torvalds 7671da177e4SLinus Torvalds if (root) { 7681da177e4SLinus Torvalds if (adjust_next) 7696b2dbba8SMichel Lespinasse vma_interval_tree_insert(next, root); 7706b2dbba8SMichel Lespinasse vma_interval_tree_insert(vma, root); 7711da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 7721da177e4SLinus Torvalds } 7731da177e4SLinus Torvalds 7741da177e4SLinus Torvalds if (remove_next) { 7751da177e4SLinus Torvalds /* 7761da177e4SLinus Torvalds * vma_merge has merged next into vma, and needs 7771da177e4SLinus Torvalds * us to remove next before dropping the locks. 7781da177e4SLinus Torvalds */ 7791da177e4SLinus Torvalds __vma_unlink(mm, next, vma); 7801da177e4SLinus Torvalds if (file) 7811da177e4SLinus Torvalds __remove_shared_vm_struct(next, file, mapping); 7821da177e4SLinus Torvalds } else if (insert) { 7831da177e4SLinus Torvalds /* 7841da177e4SLinus Torvalds * split_vma has split insert from vma, and needs 7851da177e4SLinus Torvalds * us to insert it before dropping the locks 7861da177e4SLinus Torvalds * (it may either follow vma or precede it). 7871da177e4SLinus Torvalds */ 7881da177e4SLinus Torvalds __insert_vm_struct(mm, insert); 789d3737187SMichel Lespinasse } else { 790d3737187SMichel Lespinasse if (start_changed) 791d3737187SMichel Lespinasse vma_gap_update(vma); 792d3737187SMichel Lespinasse if (end_changed) { 793d3737187SMichel Lespinasse if (!next) 794d3737187SMichel Lespinasse mm->highest_vm_end = end; 795d3737187SMichel Lespinasse else if (!adjust_next) 796d3737187SMichel Lespinasse vma_gap_update(next); 797d3737187SMichel Lespinasse } 7981da177e4SLinus Torvalds } 7991da177e4SLinus Torvalds 800bf181b9fSMichel Lespinasse if (anon_vma) { 801bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 802bf181b9fSMichel Lespinasse if (adjust_next) 803bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(next); 804012f1800SRik van Riel anon_vma_unlock(anon_vma); 805bf181b9fSMichel Lespinasse } 8061da177e4SLinus Torvalds if (mapping) 8073d48ae45SPeter Zijlstra mutex_unlock(&mapping->i_mmap_mutex); 8081da177e4SLinus Torvalds 8092b144498SSrikar Dronamraju if (root) { 8107b2d81d4SIngo Molnar uprobe_mmap(vma); 8112b144498SSrikar Dronamraju 8122b144498SSrikar Dronamraju if (adjust_next) 8137b2d81d4SIngo Molnar uprobe_mmap(next); 8142b144498SSrikar Dronamraju } 8152b144498SSrikar Dronamraju 8161da177e4SLinus Torvalds if (remove_next) { 817925d1c40SMatt Helsley if (file) { 818cbc91f71SSrikar Dronamraju uprobe_munmap(next, next->vm_start, next->vm_end); 8191da177e4SLinus Torvalds fput(file); 820925d1c40SMatt Helsley } 8215beb4930SRik van Riel if (next->anon_vma) 8225beb4930SRik van Riel anon_vma_merge(vma, next); 8231da177e4SLinus Torvalds mm->map_count--; 824f0be3d32SLee Schermerhorn mpol_put(vma_policy(next)); 8251da177e4SLinus Torvalds kmem_cache_free(vm_area_cachep, next); 8261da177e4SLinus Torvalds /* 8271da177e4SLinus Torvalds * In mprotect's case 6 (see comments on vma_merge), 8281da177e4SLinus Torvalds * we must remove another next too. It would clutter 8291da177e4SLinus Torvalds * up the code too much to do both in one go. 8301da177e4SLinus Torvalds */ 8311da177e4SLinus Torvalds next = vma->vm_next; 832d3737187SMichel Lespinasse if (remove_next == 2) 8331da177e4SLinus Torvalds goto again; 834d3737187SMichel Lespinasse else if (next) 835d3737187SMichel Lespinasse vma_gap_update(next); 836d3737187SMichel Lespinasse else 837d3737187SMichel Lespinasse mm->highest_vm_end = end; 8381da177e4SLinus Torvalds } 8392b144498SSrikar Dronamraju if (insert && file) 8407b2d81d4SIngo Molnar uprobe_mmap(insert); 8411da177e4SLinus Torvalds 8421da177e4SLinus Torvalds validate_mm(mm); 8435beb4930SRik van Riel 8445beb4930SRik van Riel return 0; 8451da177e4SLinus Torvalds } 8461da177e4SLinus Torvalds 8471da177e4SLinus Torvalds /* 8481da177e4SLinus Torvalds * If the vma has a ->close operation then the driver probably needs to release 8491da177e4SLinus Torvalds * per-vma resources, so we don't attempt to merge those. 8501da177e4SLinus Torvalds */ 8511da177e4SLinus Torvalds static inline int is_mergeable_vma(struct vm_area_struct *vma, 8521da177e4SLinus Torvalds struct file *file, unsigned long vm_flags) 8531da177e4SLinus Torvalds { 8540b173bc4SKonstantin Khlebnikov if (vma->vm_flags ^ vm_flags) 8551da177e4SLinus Torvalds return 0; 8561da177e4SLinus Torvalds if (vma->vm_file != file) 8571da177e4SLinus Torvalds return 0; 8581da177e4SLinus Torvalds if (vma->vm_ops && vma->vm_ops->close) 8591da177e4SLinus Torvalds return 0; 8601da177e4SLinus Torvalds return 1; 8611da177e4SLinus Torvalds } 8621da177e4SLinus Torvalds 8631da177e4SLinus Torvalds static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, 864965f55deSShaohua Li struct anon_vma *anon_vma2, 865965f55deSShaohua Li struct vm_area_struct *vma) 8661da177e4SLinus Torvalds { 867965f55deSShaohua Li /* 868965f55deSShaohua Li * The list_is_singular() test is to avoid merging VMA cloned from 869965f55deSShaohua Li * parents. This can improve scalability caused by anon_vma lock. 870965f55deSShaohua Li */ 871965f55deSShaohua Li if ((!anon_vma1 || !anon_vma2) && (!vma || 872965f55deSShaohua Li list_is_singular(&vma->anon_vma_chain))) 873965f55deSShaohua Li return 1; 874965f55deSShaohua Li return anon_vma1 == anon_vma2; 8751da177e4SLinus Torvalds } 8761da177e4SLinus Torvalds 8771da177e4SLinus Torvalds /* 8781da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 8791da177e4SLinus Torvalds * in front of (at a lower virtual address and file offset than) the vma. 8801da177e4SLinus Torvalds * 8811da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 8821da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 8831da177e4SLinus Torvalds * 8841da177e4SLinus Torvalds * We don't check here for the merged mmap wrapping around the end of pagecache 8851da177e4SLinus Torvalds * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which 8861da177e4SLinus Torvalds * wrap, nor mmaps which cover the final page at index -1UL. 8871da177e4SLinus Torvalds */ 8881da177e4SLinus Torvalds static int 8891da177e4SLinus Torvalds can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, 8901da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) 8911da177e4SLinus Torvalds { 8921da177e4SLinus Torvalds if (is_mergeable_vma(vma, file, vm_flags) && 893965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 8941da177e4SLinus Torvalds if (vma->vm_pgoff == vm_pgoff) 8951da177e4SLinus Torvalds return 1; 8961da177e4SLinus Torvalds } 8971da177e4SLinus Torvalds return 0; 8981da177e4SLinus Torvalds } 8991da177e4SLinus Torvalds 9001da177e4SLinus Torvalds /* 9011da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 9021da177e4SLinus Torvalds * beyond (at a higher virtual address and file offset than) the vma. 9031da177e4SLinus Torvalds * 9041da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 9051da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 9061da177e4SLinus Torvalds */ 9071da177e4SLinus Torvalds static int 9081da177e4SLinus Torvalds can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, 9091da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff) 9101da177e4SLinus Torvalds { 9111da177e4SLinus Torvalds if (is_mergeable_vma(vma, file, vm_flags) && 912965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 9131da177e4SLinus Torvalds pgoff_t vm_pglen; 9141da177e4SLinus Torvalds vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 9151da177e4SLinus Torvalds if (vma->vm_pgoff + vm_pglen == vm_pgoff) 9161da177e4SLinus Torvalds return 1; 9171da177e4SLinus Torvalds } 9181da177e4SLinus Torvalds return 0; 9191da177e4SLinus Torvalds } 9201da177e4SLinus Torvalds 9211da177e4SLinus Torvalds /* 9221da177e4SLinus Torvalds * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out 9231da177e4SLinus Torvalds * whether that can be merged with its predecessor or its successor. 9241da177e4SLinus Torvalds * Or both (it neatly fills a hole). 9251da177e4SLinus Torvalds * 9261da177e4SLinus Torvalds * In most cases - when called for mmap, brk or mremap - [addr,end) is 9271da177e4SLinus Torvalds * certain not to be mapped by the time vma_merge is called; but when 9281da177e4SLinus Torvalds * called for mprotect, it is certain to be already mapped (either at 9291da177e4SLinus Torvalds * an offset within prev, or at the start of next), and the flags of 9301da177e4SLinus Torvalds * this area are about to be changed to vm_flags - and the no-change 9311da177e4SLinus Torvalds * case has already been eliminated. 9321da177e4SLinus Torvalds * 9331da177e4SLinus Torvalds * The following mprotect cases have to be considered, where AAAA is 9341da177e4SLinus Torvalds * the area passed down from mprotect_fixup, never extending beyond one 9351da177e4SLinus Torvalds * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: 9361da177e4SLinus Torvalds * 9371da177e4SLinus Torvalds * AAAA AAAA AAAA AAAA 9381da177e4SLinus Torvalds * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX 9391da177e4SLinus Torvalds * cannot merge might become might become might become 9401da177e4SLinus Torvalds * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or 9411da177e4SLinus Torvalds * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or 9421da177e4SLinus Torvalds * mremap move: PPPPNNNNNNNN 8 9431da177e4SLinus Torvalds * AAAA 9441da177e4SLinus Torvalds * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN 9451da177e4SLinus Torvalds * might become case 1 below case 2 below case 3 below 9461da177e4SLinus Torvalds * 9471da177e4SLinus Torvalds * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX: 9481da177e4SLinus Torvalds * mprotect_fixup updates vm_flags & vm_page_prot on successful return. 9491da177e4SLinus Torvalds */ 9501da177e4SLinus Torvalds struct vm_area_struct *vma_merge(struct mm_struct *mm, 9511da177e4SLinus Torvalds struct vm_area_struct *prev, unsigned long addr, 9521da177e4SLinus Torvalds unsigned long end, unsigned long vm_flags, 9531da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, 9541da177e4SLinus Torvalds pgoff_t pgoff, struct mempolicy *policy) 9551da177e4SLinus Torvalds { 9561da177e4SLinus Torvalds pgoff_t pglen = (end - addr) >> PAGE_SHIFT; 9571da177e4SLinus Torvalds struct vm_area_struct *area, *next; 9585beb4930SRik van Riel int err; 9591da177e4SLinus Torvalds 9601da177e4SLinus Torvalds /* 9611da177e4SLinus Torvalds * We later require that vma->vm_flags == vm_flags, 9621da177e4SLinus Torvalds * so this tests vma->vm_flags & VM_SPECIAL, too. 9631da177e4SLinus Torvalds */ 9641da177e4SLinus Torvalds if (vm_flags & VM_SPECIAL) 9651da177e4SLinus Torvalds return NULL; 9661da177e4SLinus Torvalds 9671da177e4SLinus Torvalds if (prev) 9681da177e4SLinus Torvalds next = prev->vm_next; 9691da177e4SLinus Torvalds else 9701da177e4SLinus Torvalds next = mm->mmap; 9711da177e4SLinus Torvalds area = next; 9721da177e4SLinus Torvalds if (next && next->vm_end == end) /* cases 6, 7, 8 */ 9731da177e4SLinus Torvalds next = next->vm_next; 9741da177e4SLinus Torvalds 9751da177e4SLinus Torvalds /* 9761da177e4SLinus Torvalds * Can it merge with the predecessor? 9771da177e4SLinus Torvalds */ 9781da177e4SLinus Torvalds if (prev && prev->vm_end == addr && 9791da177e4SLinus Torvalds mpol_equal(vma_policy(prev), policy) && 9801da177e4SLinus Torvalds can_vma_merge_after(prev, vm_flags, 9811da177e4SLinus Torvalds anon_vma, file, pgoff)) { 9821da177e4SLinus Torvalds /* 9831da177e4SLinus Torvalds * OK, it can. Can we now merge in the successor as well? 9841da177e4SLinus Torvalds */ 9851da177e4SLinus Torvalds if (next && end == next->vm_start && 9861da177e4SLinus Torvalds mpol_equal(policy, vma_policy(next)) && 9871da177e4SLinus Torvalds can_vma_merge_before(next, vm_flags, 9881da177e4SLinus Torvalds anon_vma, file, pgoff+pglen) && 9891da177e4SLinus Torvalds is_mergeable_anon_vma(prev->anon_vma, 990965f55deSShaohua Li next->anon_vma, NULL)) { 9911da177e4SLinus Torvalds /* cases 1, 6 */ 9925beb4930SRik van Riel err = vma_adjust(prev, prev->vm_start, 9931da177e4SLinus Torvalds next->vm_end, prev->vm_pgoff, NULL); 9941da177e4SLinus Torvalds } else /* cases 2, 5, 7 */ 9955beb4930SRik van Riel err = vma_adjust(prev, prev->vm_start, 9961da177e4SLinus Torvalds end, prev->vm_pgoff, NULL); 9975beb4930SRik van Riel if (err) 9985beb4930SRik van Riel return NULL; 999b15d00b6SAndrea Arcangeli khugepaged_enter_vma_merge(prev); 10001da177e4SLinus Torvalds return prev; 10011da177e4SLinus Torvalds } 10021da177e4SLinus Torvalds 10031da177e4SLinus Torvalds /* 10041da177e4SLinus Torvalds * Can this new request be merged in front of next? 10051da177e4SLinus Torvalds */ 10061da177e4SLinus Torvalds if (next && end == next->vm_start && 10071da177e4SLinus Torvalds mpol_equal(policy, vma_policy(next)) && 10081da177e4SLinus Torvalds can_vma_merge_before(next, vm_flags, 10091da177e4SLinus Torvalds anon_vma, file, pgoff+pglen)) { 10101da177e4SLinus Torvalds if (prev && addr < prev->vm_end) /* case 4 */ 10115beb4930SRik van Riel err = vma_adjust(prev, prev->vm_start, 10121da177e4SLinus Torvalds addr, prev->vm_pgoff, NULL); 10131da177e4SLinus Torvalds else /* cases 3, 8 */ 10145beb4930SRik van Riel err = vma_adjust(area, addr, next->vm_end, 10151da177e4SLinus Torvalds next->vm_pgoff - pglen, NULL); 10165beb4930SRik van Riel if (err) 10175beb4930SRik van Riel return NULL; 1018b15d00b6SAndrea Arcangeli khugepaged_enter_vma_merge(area); 10191da177e4SLinus Torvalds return area; 10201da177e4SLinus Torvalds } 10211da177e4SLinus Torvalds 10221da177e4SLinus Torvalds return NULL; 10231da177e4SLinus Torvalds } 10241da177e4SLinus Torvalds 10251da177e4SLinus Torvalds /* 1026d0e9fe17SLinus Torvalds * Rough compatbility check to quickly see if it's even worth looking 1027d0e9fe17SLinus Torvalds * at sharing an anon_vma. 1028d0e9fe17SLinus Torvalds * 1029d0e9fe17SLinus Torvalds * They need to have the same vm_file, and the flags can only differ 1030d0e9fe17SLinus Torvalds * in things that mprotect may change. 1031d0e9fe17SLinus Torvalds * 1032d0e9fe17SLinus Torvalds * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that 1033d0e9fe17SLinus Torvalds * we can merge the two vma's. For example, we refuse to merge a vma if 1034d0e9fe17SLinus Torvalds * there is a vm_ops->close() function, because that indicates that the 1035d0e9fe17SLinus Torvalds * driver is doing some kind of reference counting. But that doesn't 1036d0e9fe17SLinus Torvalds * really matter for the anon_vma sharing case. 1037d0e9fe17SLinus Torvalds */ 1038d0e9fe17SLinus Torvalds static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) 1039d0e9fe17SLinus Torvalds { 1040d0e9fe17SLinus Torvalds return a->vm_end == b->vm_start && 1041d0e9fe17SLinus Torvalds mpol_equal(vma_policy(a), vma_policy(b)) && 1042d0e9fe17SLinus Torvalds a->vm_file == b->vm_file && 1043d0e9fe17SLinus Torvalds !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) && 1044d0e9fe17SLinus Torvalds b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); 1045d0e9fe17SLinus Torvalds } 1046d0e9fe17SLinus Torvalds 1047d0e9fe17SLinus Torvalds /* 1048d0e9fe17SLinus Torvalds * Do some basic sanity checking to see if we can re-use the anon_vma 1049d0e9fe17SLinus Torvalds * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be 1050d0e9fe17SLinus Torvalds * the same as 'old', the other will be the new one that is trying 1051d0e9fe17SLinus Torvalds * to share the anon_vma. 1052d0e9fe17SLinus Torvalds * 1053d0e9fe17SLinus Torvalds * NOTE! This runs with mm_sem held for reading, so it is possible that 1054d0e9fe17SLinus Torvalds * the anon_vma of 'old' is concurrently in the process of being set up 1055d0e9fe17SLinus Torvalds * by another page fault trying to merge _that_. But that's ok: if it 1056d0e9fe17SLinus Torvalds * is being set up, that automatically means that it will be a singleton 1057d0e9fe17SLinus Torvalds * acceptable for merging, so we can do all of this optimistically. But 1058d0e9fe17SLinus Torvalds * we do that ACCESS_ONCE() to make sure that we never re-load the pointer. 1059d0e9fe17SLinus Torvalds * 1060d0e9fe17SLinus Torvalds * IOW: that the "list_is_singular()" test on the anon_vma_chain only 1061d0e9fe17SLinus Torvalds * matters for the 'stable anon_vma' case (ie the thing we want to avoid 1062d0e9fe17SLinus Torvalds * is to return an anon_vma that is "complex" due to having gone through 1063d0e9fe17SLinus Torvalds * a fork). 1064d0e9fe17SLinus Torvalds * 1065d0e9fe17SLinus Torvalds * We also make sure that the two vma's are compatible (adjacent, 1066d0e9fe17SLinus Torvalds * and with the same memory policies). That's all stable, even with just 1067d0e9fe17SLinus Torvalds * a read lock on the mm_sem. 1068d0e9fe17SLinus Torvalds */ 1069d0e9fe17SLinus Torvalds static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) 1070d0e9fe17SLinus Torvalds { 1071d0e9fe17SLinus Torvalds if (anon_vma_compatible(a, b)) { 1072d0e9fe17SLinus Torvalds struct anon_vma *anon_vma = ACCESS_ONCE(old->anon_vma); 1073d0e9fe17SLinus Torvalds 1074d0e9fe17SLinus Torvalds if (anon_vma && list_is_singular(&old->anon_vma_chain)) 1075d0e9fe17SLinus Torvalds return anon_vma; 1076d0e9fe17SLinus Torvalds } 1077d0e9fe17SLinus Torvalds return NULL; 1078d0e9fe17SLinus Torvalds } 1079d0e9fe17SLinus Torvalds 1080d0e9fe17SLinus Torvalds /* 10811da177e4SLinus Torvalds * find_mergeable_anon_vma is used by anon_vma_prepare, to check 10821da177e4SLinus Torvalds * neighbouring vmas for a suitable anon_vma, before it goes off 10831da177e4SLinus Torvalds * to allocate a new anon_vma. It checks because a repetitive 10841da177e4SLinus Torvalds * sequence of mprotects and faults may otherwise lead to distinct 10851da177e4SLinus Torvalds * anon_vmas being allocated, preventing vma merge in subsequent 10861da177e4SLinus Torvalds * mprotect. 10871da177e4SLinus Torvalds */ 10881da177e4SLinus Torvalds struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) 10891da177e4SLinus Torvalds { 1090d0e9fe17SLinus Torvalds struct anon_vma *anon_vma; 10911da177e4SLinus Torvalds struct vm_area_struct *near; 10921da177e4SLinus Torvalds 10931da177e4SLinus Torvalds near = vma->vm_next; 10941da177e4SLinus Torvalds if (!near) 10951da177e4SLinus Torvalds goto try_prev; 10961da177e4SLinus Torvalds 1097d0e9fe17SLinus Torvalds anon_vma = reusable_anon_vma(near, vma, near); 1098d0e9fe17SLinus Torvalds if (anon_vma) 1099d0e9fe17SLinus Torvalds return anon_vma; 11001da177e4SLinus Torvalds try_prev: 11019be34c9dSLinus Torvalds near = vma->vm_prev; 11021da177e4SLinus Torvalds if (!near) 11031da177e4SLinus Torvalds goto none; 11041da177e4SLinus Torvalds 1105d0e9fe17SLinus Torvalds anon_vma = reusable_anon_vma(near, near, vma); 1106d0e9fe17SLinus Torvalds if (anon_vma) 1107d0e9fe17SLinus Torvalds return anon_vma; 11081da177e4SLinus Torvalds none: 11091da177e4SLinus Torvalds /* 11101da177e4SLinus Torvalds * There's no absolute need to look only at touching neighbours: 11111da177e4SLinus Torvalds * we could search further afield for "compatible" anon_vmas. 11121da177e4SLinus Torvalds * But it would probably just be a waste of time searching, 11131da177e4SLinus Torvalds * or lead to too many vmas hanging off the same anon_vma. 11141da177e4SLinus Torvalds * We're trying to allow mprotect remerging later on, 11151da177e4SLinus Torvalds * not trying to minimize memory used for anon_vmas. 11161da177e4SLinus Torvalds */ 11171da177e4SLinus Torvalds return NULL; 11181da177e4SLinus Torvalds } 11191da177e4SLinus Torvalds 11201da177e4SLinus Torvalds #ifdef CONFIG_PROC_FS 1121ab50b8edSHugh Dickins void vm_stat_account(struct mm_struct *mm, unsigned long flags, 11221da177e4SLinus Torvalds struct file *file, long pages) 11231da177e4SLinus Torvalds { 11241da177e4SLinus Torvalds const unsigned long stack_flags 11251da177e4SLinus Torvalds = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); 11261da177e4SLinus Torvalds 112744de9d0cSHuang Shijie mm->total_vm += pages; 112844de9d0cSHuang Shijie 11291da177e4SLinus Torvalds if (file) { 11301da177e4SLinus Torvalds mm->shared_vm += pages; 11311da177e4SLinus Torvalds if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) 11321da177e4SLinus Torvalds mm->exec_vm += pages; 11331da177e4SLinus Torvalds } else if (flags & stack_flags) 11341da177e4SLinus Torvalds mm->stack_vm += pages; 11351da177e4SLinus Torvalds } 11361da177e4SLinus Torvalds #endif /* CONFIG_PROC_FS */ 11371da177e4SLinus Torvalds 11381da177e4SLinus Torvalds /* 113940401530SAl Viro * If a hint addr is less than mmap_min_addr change hint to be as 114040401530SAl Viro * low as possible but still greater than mmap_min_addr 114140401530SAl Viro */ 114240401530SAl Viro static inline unsigned long round_hint_to_min(unsigned long hint) 114340401530SAl Viro { 114440401530SAl Viro hint &= PAGE_MASK; 114540401530SAl Viro if (((void *)hint != NULL) && 114640401530SAl Viro (hint < mmap_min_addr)) 114740401530SAl Viro return PAGE_ALIGN(mmap_min_addr); 114840401530SAl Viro return hint; 114940401530SAl Viro } 115040401530SAl Viro 115140401530SAl Viro /* 115227f5de79SJianjun Kong * The caller must hold down_write(¤t->mm->mmap_sem). 11531da177e4SLinus Torvalds */ 11541da177e4SLinus Torvalds 1155e3fc629dSAl Viro unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, 11561da177e4SLinus Torvalds unsigned long len, unsigned long prot, 1157*bebeb3d6SMichel Lespinasse unsigned long flags, unsigned long pgoff, 1158*bebeb3d6SMichel Lespinasse bool *populate) 11591da177e4SLinus Torvalds { 11601da177e4SLinus Torvalds struct mm_struct * mm = current->mm; 11611da177e4SLinus Torvalds struct inode *inode; 1162ca16d140SKOSAKI Motohiro vm_flags_t vm_flags; 11631da177e4SLinus Torvalds 1164*bebeb3d6SMichel Lespinasse *populate = false; 1165*bebeb3d6SMichel Lespinasse 11661da177e4SLinus Torvalds /* 11671da177e4SLinus Torvalds * Does the application expect PROT_READ to imply PROT_EXEC? 11681da177e4SLinus Torvalds * 11691da177e4SLinus Torvalds * (the exception is when the underlying filesystem is noexec 11701da177e4SLinus Torvalds * mounted, in which case we dont add PROT_EXEC.) 11711da177e4SLinus Torvalds */ 11721da177e4SLinus Torvalds if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) 1173d3ac7f89SJosef "Jeff" Sipek if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) 11741da177e4SLinus Torvalds prot |= PROT_EXEC; 11751da177e4SLinus Torvalds 11761da177e4SLinus Torvalds if (!len) 11771da177e4SLinus Torvalds return -EINVAL; 11781da177e4SLinus Torvalds 11797cd94146SEric Paris if (!(flags & MAP_FIXED)) 11807cd94146SEric Paris addr = round_hint_to_min(addr); 11817cd94146SEric Paris 11821da177e4SLinus Torvalds /* Careful about overflows.. */ 11831da177e4SLinus Torvalds len = PAGE_ALIGN(len); 11849206de95SAl Viro if (!len) 11851da177e4SLinus Torvalds return -ENOMEM; 11861da177e4SLinus Torvalds 11871da177e4SLinus Torvalds /* offset overflow? */ 11881da177e4SLinus Torvalds if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) 11891da177e4SLinus Torvalds return -EOVERFLOW; 11901da177e4SLinus Torvalds 11911da177e4SLinus Torvalds /* Too many mappings? */ 11921da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 11931da177e4SLinus Torvalds return -ENOMEM; 11941da177e4SLinus Torvalds 11951da177e4SLinus Torvalds /* Obtain the address to map to. we verify (or select) it and ensure 11961da177e4SLinus Torvalds * that it represents a valid section of the address space. 11971da177e4SLinus Torvalds */ 11981da177e4SLinus Torvalds addr = get_unmapped_area(file, addr, len, pgoff, flags); 11991da177e4SLinus Torvalds if (addr & ~PAGE_MASK) 12001da177e4SLinus Torvalds return addr; 12011da177e4SLinus Torvalds 12021da177e4SLinus Torvalds /* Do simple checking here so the lower-level routines won't have 12031da177e4SLinus Torvalds * to. we assume access permissions have been handled by the open 12041da177e4SLinus Torvalds * of the memory object, so we don't do any here. 12051da177e4SLinus Torvalds */ 12061da177e4SLinus Torvalds vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | 12071da177e4SLinus Torvalds mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; 12081da177e4SLinus Torvalds 1209cdf7b341SHuang Shijie if (flags & MAP_LOCKED) 12101da177e4SLinus Torvalds if (!can_do_mlock()) 12111da177e4SLinus Torvalds return -EPERM; 1212ba470de4SRik van Riel 12131da177e4SLinus Torvalds /* mlock MCL_FUTURE? */ 12141da177e4SLinus Torvalds if (vm_flags & VM_LOCKED) { 12151da177e4SLinus Torvalds unsigned long locked, lock_limit; 121693ea1d0aSChris Wright locked = len >> PAGE_SHIFT; 121793ea1d0aSChris Wright locked += mm->locked_vm; 121859e99e5bSJiri Slaby lock_limit = rlimit(RLIMIT_MEMLOCK); 121993ea1d0aSChris Wright lock_limit >>= PAGE_SHIFT; 12201da177e4SLinus Torvalds if (locked > lock_limit && !capable(CAP_IPC_LOCK)) 12211da177e4SLinus Torvalds return -EAGAIN; 12221da177e4SLinus Torvalds } 12231da177e4SLinus Torvalds 1224d3ac7f89SJosef "Jeff" Sipek inode = file ? file->f_path.dentry->d_inode : NULL; 12251da177e4SLinus Torvalds 12261da177e4SLinus Torvalds if (file) { 12271da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 12281da177e4SLinus Torvalds case MAP_SHARED: 12291da177e4SLinus Torvalds if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) 12301da177e4SLinus Torvalds return -EACCES; 12311da177e4SLinus Torvalds 12321da177e4SLinus Torvalds /* 12331da177e4SLinus Torvalds * Make sure we don't allow writing to an append-only 12341da177e4SLinus Torvalds * file.. 12351da177e4SLinus Torvalds */ 12361da177e4SLinus Torvalds if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) 12371da177e4SLinus Torvalds return -EACCES; 12381da177e4SLinus Torvalds 12391da177e4SLinus Torvalds /* 12401da177e4SLinus Torvalds * Make sure there are no mandatory locks on the file. 12411da177e4SLinus Torvalds */ 12421da177e4SLinus Torvalds if (locks_verify_locked(inode)) 12431da177e4SLinus Torvalds return -EAGAIN; 12441da177e4SLinus Torvalds 12451da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 12461da177e4SLinus Torvalds if (!(file->f_mode & FMODE_WRITE)) 12471da177e4SLinus Torvalds vm_flags &= ~(VM_MAYWRITE | VM_SHARED); 12481da177e4SLinus Torvalds 12491da177e4SLinus Torvalds /* fall through */ 12501da177e4SLinus Torvalds case MAP_PRIVATE: 12511da177e4SLinus Torvalds if (!(file->f_mode & FMODE_READ)) 12521da177e4SLinus Torvalds return -EACCES; 1253d3ac7f89SJosef "Jeff" Sipek if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { 125480c5606cSLinus Torvalds if (vm_flags & VM_EXEC) 125580c5606cSLinus Torvalds return -EPERM; 125680c5606cSLinus Torvalds vm_flags &= ~VM_MAYEXEC; 125780c5606cSLinus Torvalds } 125880c5606cSLinus Torvalds 125980c5606cSLinus Torvalds if (!file->f_op || !file->f_op->mmap) 126080c5606cSLinus Torvalds return -ENODEV; 12611da177e4SLinus Torvalds break; 12621da177e4SLinus Torvalds 12631da177e4SLinus Torvalds default: 12641da177e4SLinus Torvalds return -EINVAL; 12651da177e4SLinus Torvalds } 12661da177e4SLinus Torvalds } else { 12671da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 12681da177e4SLinus Torvalds case MAP_SHARED: 1269ce363942STejun Heo /* 1270ce363942STejun Heo * Ignore pgoff. 1271ce363942STejun Heo */ 1272ce363942STejun Heo pgoff = 0; 12731da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 12741da177e4SLinus Torvalds break; 12751da177e4SLinus Torvalds case MAP_PRIVATE: 12761da177e4SLinus Torvalds /* 12771da177e4SLinus Torvalds * Set pgoff according to addr for anon_vma. 12781da177e4SLinus Torvalds */ 12791da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 12801da177e4SLinus Torvalds break; 12811da177e4SLinus Torvalds default: 12821da177e4SLinus Torvalds return -EINVAL; 12831da177e4SLinus Torvalds } 12841da177e4SLinus Torvalds } 12851da177e4SLinus Torvalds 1286*bebeb3d6SMichel Lespinasse addr = mmap_region(file, addr, len, flags, vm_flags, pgoff); 1287*bebeb3d6SMichel Lespinasse if (!IS_ERR_VALUE(addr) && 1288*bebeb3d6SMichel Lespinasse ((vm_flags & VM_LOCKED) || 1289*bebeb3d6SMichel Lespinasse (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) 1290*bebeb3d6SMichel Lespinasse *populate = true; 1291*bebeb3d6SMichel Lespinasse return addr; 12920165ab44SMiklos Szeredi } 12936be5ceb0SLinus Torvalds 129466f0dc48SHugh Dickins SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, 129566f0dc48SHugh Dickins unsigned long, prot, unsigned long, flags, 129666f0dc48SHugh Dickins unsigned long, fd, unsigned long, pgoff) 129766f0dc48SHugh Dickins { 129866f0dc48SHugh Dickins struct file *file = NULL; 129966f0dc48SHugh Dickins unsigned long retval = -EBADF; 130066f0dc48SHugh Dickins 130166f0dc48SHugh Dickins if (!(flags & MAP_ANONYMOUS)) { 1302120a795dSAl Viro audit_mmap_fd(fd, flags); 130366f0dc48SHugh Dickins if (unlikely(flags & MAP_HUGETLB)) 130466f0dc48SHugh Dickins return -EINVAL; 130566f0dc48SHugh Dickins file = fget(fd); 130666f0dc48SHugh Dickins if (!file) 130766f0dc48SHugh Dickins goto out; 130866f0dc48SHugh Dickins } else if (flags & MAP_HUGETLB) { 130966f0dc48SHugh Dickins struct user_struct *user = NULL; 131066f0dc48SHugh Dickins /* 131166f0dc48SHugh Dickins * VM_NORESERVE is used because the reservations will be 131266f0dc48SHugh Dickins * taken when vm_ops->mmap() is called 131366f0dc48SHugh Dickins * A dummy user value is used because we are not locking 131466f0dc48SHugh Dickins * memory so no accounting is necessary 131566f0dc48SHugh Dickins */ 131640716e29SSteven Truelove file = hugetlb_file_setup(HUGETLB_ANON_FILE, addr, len, 131742d7395fSAndi Kleen VM_NORESERVE, 131842d7395fSAndi Kleen &user, HUGETLB_ANONHUGE_INODE, 131942d7395fSAndi Kleen (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 132066f0dc48SHugh Dickins if (IS_ERR(file)) 132166f0dc48SHugh Dickins return PTR_ERR(file); 132266f0dc48SHugh Dickins } 132366f0dc48SHugh Dickins 132466f0dc48SHugh Dickins flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); 132566f0dc48SHugh Dickins 1326eb36c587SAl Viro retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); 132766f0dc48SHugh Dickins if (file) 132866f0dc48SHugh Dickins fput(file); 132966f0dc48SHugh Dickins out: 133066f0dc48SHugh Dickins return retval; 133166f0dc48SHugh Dickins } 133266f0dc48SHugh Dickins 1333a4679373SChristoph Hellwig #ifdef __ARCH_WANT_SYS_OLD_MMAP 1334a4679373SChristoph Hellwig struct mmap_arg_struct { 1335a4679373SChristoph Hellwig unsigned long addr; 1336a4679373SChristoph Hellwig unsigned long len; 1337a4679373SChristoph Hellwig unsigned long prot; 1338a4679373SChristoph Hellwig unsigned long flags; 1339a4679373SChristoph Hellwig unsigned long fd; 1340a4679373SChristoph Hellwig unsigned long offset; 1341a4679373SChristoph Hellwig }; 1342a4679373SChristoph Hellwig 1343a4679373SChristoph Hellwig SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) 1344a4679373SChristoph Hellwig { 1345a4679373SChristoph Hellwig struct mmap_arg_struct a; 1346a4679373SChristoph Hellwig 1347a4679373SChristoph Hellwig if (copy_from_user(&a, arg, sizeof(a))) 1348a4679373SChristoph Hellwig return -EFAULT; 1349a4679373SChristoph Hellwig if (a.offset & ~PAGE_MASK) 1350a4679373SChristoph Hellwig return -EINVAL; 1351a4679373SChristoph Hellwig 1352a4679373SChristoph Hellwig return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, 1353a4679373SChristoph Hellwig a.offset >> PAGE_SHIFT); 1354a4679373SChristoph Hellwig } 1355a4679373SChristoph Hellwig #endif /* __ARCH_WANT_SYS_OLD_MMAP */ 1356a4679373SChristoph Hellwig 13574e950f6fSAlexey Dobriyan /* 13584e950f6fSAlexey Dobriyan * Some shared mappigns will want the pages marked read-only 13594e950f6fSAlexey Dobriyan * to track write events. If so, we'll downgrade vm_page_prot 13604e950f6fSAlexey Dobriyan * to the private version (using protection_map[] without the 13614e950f6fSAlexey Dobriyan * VM_SHARED bit). 13624e950f6fSAlexey Dobriyan */ 13634e950f6fSAlexey Dobriyan int vma_wants_writenotify(struct vm_area_struct *vma) 13644e950f6fSAlexey Dobriyan { 1365ca16d140SKOSAKI Motohiro vm_flags_t vm_flags = vma->vm_flags; 13664e950f6fSAlexey Dobriyan 13674e950f6fSAlexey Dobriyan /* If it was private or non-writable, the write bit is already clear */ 13684e950f6fSAlexey Dobriyan if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) 13694e950f6fSAlexey Dobriyan return 0; 13704e950f6fSAlexey Dobriyan 13714e950f6fSAlexey Dobriyan /* The backer wishes to know when pages are first written to? */ 13724e950f6fSAlexey Dobriyan if (vma->vm_ops && vma->vm_ops->page_mkwrite) 13734e950f6fSAlexey Dobriyan return 1; 13744e950f6fSAlexey Dobriyan 13754e950f6fSAlexey Dobriyan /* The open routine did something to the protections already? */ 13764e950f6fSAlexey Dobriyan if (pgprot_val(vma->vm_page_prot) != 13773ed75eb8SColy Li pgprot_val(vm_get_page_prot(vm_flags))) 13784e950f6fSAlexey Dobriyan return 0; 13794e950f6fSAlexey Dobriyan 13804e950f6fSAlexey Dobriyan /* Specialty mapping? */ 13814b6e1e37SKonstantin Khlebnikov if (vm_flags & VM_PFNMAP) 13824e950f6fSAlexey Dobriyan return 0; 13834e950f6fSAlexey Dobriyan 13844e950f6fSAlexey Dobriyan /* Can the mapping track the dirty pages? */ 13854e950f6fSAlexey Dobriyan return vma->vm_file && vma->vm_file->f_mapping && 13864e950f6fSAlexey Dobriyan mapping_cap_account_dirty(vma->vm_file->f_mapping); 13874e950f6fSAlexey Dobriyan } 13884e950f6fSAlexey Dobriyan 1389fc8744adSLinus Torvalds /* 1390fc8744adSLinus Torvalds * We account for memory if it's a private writeable mapping, 13915a6fe125SMel Gorman * not hugepages and VM_NORESERVE wasn't set. 1392fc8744adSLinus Torvalds */ 1393ca16d140SKOSAKI Motohiro static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) 1394fc8744adSLinus Torvalds { 13955a6fe125SMel Gorman /* 13965a6fe125SMel Gorman * hugetlb has its own accounting separate from the core VM 13975a6fe125SMel Gorman * VM_HUGETLB may not be set yet so we cannot check for that flag. 13985a6fe125SMel Gorman */ 13995a6fe125SMel Gorman if (file && is_file_hugepages(file)) 14005a6fe125SMel Gorman return 0; 14015a6fe125SMel Gorman 1402fc8744adSLinus Torvalds return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; 1403fc8744adSLinus Torvalds } 1404fc8744adSLinus Torvalds 14050165ab44SMiklos Szeredi unsigned long mmap_region(struct file *file, unsigned long addr, 14060165ab44SMiklos Szeredi unsigned long len, unsigned long flags, 1407ca16d140SKOSAKI Motohiro vm_flags_t vm_flags, unsigned long pgoff) 14080165ab44SMiklos Szeredi { 14090165ab44SMiklos Szeredi struct mm_struct *mm = current->mm; 14100165ab44SMiklos Szeredi struct vm_area_struct *vma, *prev; 14110165ab44SMiklos Szeredi int correct_wcount = 0; 14120165ab44SMiklos Szeredi int error; 14130165ab44SMiklos Szeredi struct rb_node **rb_link, *rb_parent; 14140165ab44SMiklos Szeredi unsigned long charged = 0; 14150165ab44SMiklos Szeredi struct inode *inode = file ? file->f_path.dentry->d_inode : NULL; 14160165ab44SMiklos Szeredi 14171da177e4SLinus Torvalds /* Clear old maps */ 14181da177e4SLinus Torvalds error = -ENOMEM; 14191da177e4SLinus Torvalds munmap_back: 14206597d783SHugh Dickins if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { 14211da177e4SLinus Torvalds if (do_munmap(mm, addr, len)) 14221da177e4SLinus Torvalds return -ENOMEM; 14231da177e4SLinus Torvalds goto munmap_back; 14241da177e4SLinus Torvalds } 14251da177e4SLinus Torvalds 14261da177e4SLinus Torvalds /* Check against address space limit. */ 1427119f657cSakpm@osdl.org if (!may_expand_vm(mm, len >> PAGE_SHIFT)) 14281da177e4SLinus Torvalds return -ENOMEM; 14291da177e4SLinus Torvalds 1430fc8744adSLinus Torvalds /* 1431fc8744adSLinus Torvalds * Set 'VM_NORESERVE' if we should not account for the 14325a6fe125SMel Gorman * memory use of this mapping. 1433fc8744adSLinus Torvalds */ 14345a6fe125SMel Gorman if ((flags & MAP_NORESERVE)) { 14355a6fe125SMel Gorman /* We honor MAP_NORESERVE if allowed to overcommit */ 14365a6fe125SMel Gorman if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) 1437fc8744adSLinus Torvalds vm_flags |= VM_NORESERVE; 14385a6fe125SMel Gorman 14395a6fe125SMel Gorman /* hugetlb applies strict overcommit unless MAP_NORESERVE */ 14405a6fe125SMel Gorman if (file && is_file_hugepages(file)) 1441cdfd4325SAndy Whitcroft vm_flags |= VM_NORESERVE; 14425a6fe125SMel Gorman } 1443cdfd4325SAndy Whitcroft 14441da177e4SLinus Torvalds /* 14451da177e4SLinus Torvalds * Private writable mapping: check memory availability 14461da177e4SLinus Torvalds */ 14475a6fe125SMel Gorman if (accountable_mapping(file, vm_flags)) { 14481da177e4SLinus Torvalds charged = len >> PAGE_SHIFT; 1449191c5424SAl Viro if (security_vm_enough_memory_mm(mm, charged)) 14501da177e4SLinus Torvalds return -ENOMEM; 14511da177e4SLinus Torvalds vm_flags |= VM_ACCOUNT; 14521da177e4SLinus Torvalds } 14531da177e4SLinus Torvalds 14541da177e4SLinus Torvalds /* 1455de33c8dbSLinus Torvalds * Can we just expand an old mapping? 14561da177e4SLinus Torvalds */ 1457de33c8dbSLinus Torvalds vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL); 1458ba470de4SRik van Riel if (vma) 14591da177e4SLinus Torvalds goto out; 14601da177e4SLinus Torvalds 14611da177e4SLinus Torvalds /* 14621da177e4SLinus Torvalds * Determine the object being mapped and call the appropriate 14631da177e4SLinus Torvalds * specific mapper. the address has already been validated, but 14641da177e4SLinus Torvalds * not unmapped, but the maps are removed from the list. 14651da177e4SLinus Torvalds */ 1466c5e3b83eSPekka Enberg vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); 14671da177e4SLinus Torvalds if (!vma) { 14681da177e4SLinus Torvalds error = -ENOMEM; 14691da177e4SLinus Torvalds goto unacct_error; 14701da177e4SLinus Torvalds } 14711da177e4SLinus Torvalds 14721da177e4SLinus Torvalds vma->vm_mm = mm; 14731da177e4SLinus Torvalds vma->vm_start = addr; 14741da177e4SLinus Torvalds vma->vm_end = addr + len; 14751da177e4SLinus Torvalds vma->vm_flags = vm_flags; 14763ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(vm_flags); 14771da177e4SLinus Torvalds vma->vm_pgoff = pgoff; 14785beb4930SRik van Riel INIT_LIST_HEAD(&vma->anon_vma_chain); 14791da177e4SLinus Torvalds 1480ce8fea7aSHugh Dickins error = -EINVAL; /* when rejecting VM_GROWSDOWN|VM_GROWSUP */ 1481ce8fea7aSHugh Dickins 14821da177e4SLinus Torvalds if (file) { 14831da177e4SLinus Torvalds if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 14841da177e4SLinus Torvalds goto free_vma; 14851da177e4SLinus Torvalds if (vm_flags & VM_DENYWRITE) { 14861da177e4SLinus Torvalds error = deny_write_access(file); 14871da177e4SLinus Torvalds if (error) 14881da177e4SLinus Torvalds goto free_vma; 14891da177e4SLinus Torvalds correct_wcount = 1; 14901da177e4SLinus Torvalds } 1491cb0942b8SAl Viro vma->vm_file = get_file(file); 14921da177e4SLinus Torvalds error = file->f_op->mmap(file, vma); 14931da177e4SLinus Torvalds if (error) 14941da177e4SLinus Torvalds goto unmap_and_free_vma; 14951da177e4SLinus Torvalds 14961da177e4SLinus Torvalds /* Can addr have changed?? 14971da177e4SLinus Torvalds * 14981da177e4SLinus Torvalds * Answer: Yes, several device drivers can do it in their 14991da177e4SLinus Torvalds * f_op->mmap method. -DaveM 15002897b4d2SJoonsoo Kim * Bug: If addr is changed, prev, rb_link, rb_parent should 15012897b4d2SJoonsoo Kim * be updated for vma_link() 15021da177e4SLinus Torvalds */ 15032897b4d2SJoonsoo Kim WARN_ON_ONCE(addr != vma->vm_start); 15042897b4d2SJoonsoo Kim 15051da177e4SLinus Torvalds addr = vma->vm_start; 15061da177e4SLinus Torvalds pgoff = vma->vm_pgoff; 15071da177e4SLinus Torvalds vm_flags = vma->vm_flags; 1508f8dbf0a7SHuang Shijie } else if (vm_flags & VM_SHARED) { 1509835ee797SAl Viro if (unlikely(vm_flags & (VM_GROWSDOWN|VM_GROWSUP))) 1510835ee797SAl Viro goto free_vma; 1511f8dbf0a7SHuang Shijie error = shmem_zero_setup(vma); 1512f8dbf0a7SHuang Shijie if (error) 1513f8dbf0a7SHuang Shijie goto free_vma; 1514f8dbf0a7SHuang Shijie } 15151da177e4SLinus Torvalds 1516c9d0bf24SMagnus Damm if (vma_wants_writenotify(vma)) { 1517c9d0bf24SMagnus Damm pgprot_t pprot = vma->vm_page_prot; 1518c9d0bf24SMagnus Damm 1519c9d0bf24SMagnus Damm /* Can vma->vm_page_prot have changed?? 1520c9d0bf24SMagnus Damm * 1521c9d0bf24SMagnus Damm * Answer: Yes, drivers may have changed it in their 1522c9d0bf24SMagnus Damm * f_op->mmap method. 1523c9d0bf24SMagnus Damm * 1524c9d0bf24SMagnus Damm * Ensures that vmas marked as uncached stay that way. 1525c9d0bf24SMagnus Damm */ 15261ddd439eSHugh Dickins vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); 1527c9d0bf24SMagnus Damm if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot))) 1528c9d0bf24SMagnus Damm vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 1529c9d0bf24SMagnus Damm } 1530d08b3851SPeter Zijlstra 15314d3d5b41SOleg Nesterov vma_link(mm, vma, prev, rb_link, rb_parent); 15324d3d5b41SOleg Nesterov file = vma->vm_file; 15334d3d5b41SOleg Nesterov 15344d3d5b41SOleg Nesterov /* Once vma denies write, undo our temporary denial count */ 15354d3d5b41SOleg Nesterov if (correct_wcount) 15364d3d5b41SOleg Nesterov atomic_inc(&inode->i_writecount); 15371da177e4SLinus Torvalds out: 1538cdd6c482SIngo Molnar perf_event_mmap(vma); 15390a4a9391SPeter Zijlstra 1540ab50b8edSHugh Dickins vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); 15411da177e4SLinus Torvalds if (vm_flags & VM_LOCKED) { 1542*bebeb3d6SMichel Lespinasse if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || 1543*bebeb3d6SMichel Lespinasse vma == get_gate_vma(current->mm))) 154406f9d8c2SKOSAKI Motohiro mm->locked_vm += (len >> PAGE_SHIFT); 1545*bebeb3d6SMichel Lespinasse else 1546*bebeb3d6SMichel Lespinasse vma->vm_flags &= ~VM_LOCKED; 1547*bebeb3d6SMichel Lespinasse } 15482b144498SSrikar Dronamraju 1549c7a3a88cSOleg Nesterov if (file) 1550c7a3a88cSOleg Nesterov uprobe_mmap(vma); 15512b144498SSrikar Dronamraju 15521da177e4SLinus Torvalds return addr; 15531da177e4SLinus Torvalds 15541da177e4SLinus Torvalds unmap_and_free_vma: 15551da177e4SLinus Torvalds if (correct_wcount) 15561da177e4SLinus Torvalds atomic_inc(&inode->i_writecount); 15571da177e4SLinus Torvalds vma->vm_file = NULL; 15581da177e4SLinus Torvalds fput(file); 15591da177e4SLinus Torvalds 15601da177e4SLinus Torvalds /* Undo any partial mapping done by a device driver. */ 1561e0da382cSHugh Dickins unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end); 1562e0da382cSHugh Dickins charged = 0; 15631da177e4SLinus Torvalds free_vma: 15641da177e4SLinus Torvalds kmem_cache_free(vm_area_cachep, vma); 15651da177e4SLinus Torvalds unacct_error: 15661da177e4SLinus Torvalds if (charged) 15671da177e4SLinus Torvalds vm_unacct_memory(charged); 15681da177e4SLinus Torvalds return error; 15691da177e4SLinus Torvalds } 15701da177e4SLinus Torvalds 1571db4fbfb9SMichel Lespinasse unsigned long unmapped_area(struct vm_unmapped_area_info *info) 1572db4fbfb9SMichel Lespinasse { 1573db4fbfb9SMichel Lespinasse /* 1574db4fbfb9SMichel Lespinasse * We implement the search by looking for an rbtree node that 1575db4fbfb9SMichel Lespinasse * immediately follows a suitable gap. That is, 1576db4fbfb9SMichel Lespinasse * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length; 1577db4fbfb9SMichel Lespinasse * - gap_end = vma->vm_start >= info->low_limit + length; 1578db4fbfb9SMichel Lespinasse * - gap_end - gap_start >= length 1579db4fbfb9SMichel Lespinasse */ 1580db4fbfb9SMichel Lespinasse 1581db4fbfb9SMichel Lespinasse struct mm_struct *mm = current->mm; 1582db4fbfb9SMichel Lespinasse struct vm_area_struct *vma; 1583db4fbfb9SMichel Lespinasse unsigned long length, low_limit, high_limit, gap_start, gap_end; 1584db4fbfb9SMichel Lespinasse 1585db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1586db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1587db4fbfb9SMichel Lespinasse if (length < info->length) 1588db4fbfb9SMichel Lespinasse return -ENOMEM; 1589db4fbfb9SMichel Lespinasse 1590db4fbfb9SMichel Lespinasse /* Adjust search limits by the desired length */ 1591db4fbfb9SMichel Lespinasse if (info->high_limit < length) 1592db4fbfb9SMichel Lespinasse return -ENOMEM; 1593db4fbfb9SMichel Lespinasse high_limit = info->high_limit - length; 1594db4fbfb9SMichel Lespinasse 1595db4fbfb9SMichel Lespinasse if (info->low_limit > high_limit) 1596db4fbfb9SMichel Lespinasse return -ENOMEM; 1597db4fbfb9SMichel Lespinasse low_limit = info->low_limit + length; 1598db4fbfb9SMichel Lespinasse 1599db4fbfb9SMichel Lespinasse /* Check if rbtree root looks promising */ 1600db4fbfb9SMichel Lespinasse if (RB_EMPTY_ROOT(&mm->mm_rb)) 1601db4fbfb9SMichel Lespinasse goto check_highest; 1602db4fbfb9SMichel Lespinasse vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); 1603db4fbfb9SMichel Lespinasse if (vma->rb_subtree_gap < length) 1604db4fbfb9SMichel Lespinasse goto check_highest; 1605db4fbfb9SMichel Lespinasse 1606db4fbfb9SMichel Lespinasse while (true) { 1607db4fbfb9SMichel Lespinasse /* Visit left subtree if it looks promising */ 1608db4fbfb9SMichel Lespinasse gap_end = vma->vm_start; 1609db4fbfb9SMichel Lespinasse if (gap_end >= low_limit && vma->vm_rb.rb_left) { 1610db4fbfb9SMichel Lespinasse struct vm_area_struct *left = 1611db4fbfb9SMichel Lespinasse rb_entry(vma->vm_rb.rb_left, 1612db4fbfb9SMichel Lespinasse struct vm_area_struct, vm_rb); 1613db4fbfb9SMichel Lespinasse if (left->rb_subtree_gap >= length) { 1614db4fbfb9SMichel Lespinasse vma = left; 1615db4fbfb9SMichel Lespinasse continue; 1616db4fbfb9SMichel Lespinasse } 1617db4fbfb9SMichel Lespinasse } 1618db4fbfb9SMichel Lespinasse 1619db4fbfb9SMichel Lespinasse gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; 1620db4fbfb9SMichel Lespinasse check_current: 1621db4fbfb9SMichel Lespinasse /* Check if current node has a suitable gap */ 1622db4fbfb9SMichel Lespinasse if (gap_start > high_limit) 1623db4fbfb9SMichel Lespinasse return -ENOMEM; 1624db4fbfb9SMichel Lespinasse if (gap_end >= low_limit && gap_end - gap_start >= length) 1625db4fbfb9SMichel Lespinasse goto found; 1626db4fbfb9SMichel Lespinasse 1627db4fbfb9SMichel Lespinasse /* Visit right subtree if it looks promising */ 1628db4fbfb9SMichel Lespinasse if (vma->vm_rb.rb_right) { 1629db4fbfb9SMichel Lespinasse struct vm_area_struct *right = 1630db4fbfb9SMichel Lespinasse rb_entry(vma->vm_rb.rb_right, 1631db4fbfb9SMichel Lespinasse struct vm_area_struct, vm_rb); 1632db4fbfb9SMichel Lespinasse if (right->rb_subtree_gap >= length) { 1633db4fbfb9SMichel Lespinasse vma = right; 1634db4fbfb9SMichel Lespinasse continue; 1635db4fbfb9SMichel Lespinasse } 1636db4fbfb9SMichel Lespinasse } 1637db4fbfb9SMichel Lespinasse 1638db4fbfb9SMichel Lespinasse /* Go back up the rbtree to find next candidate node */ 1639db4fbfb9SMichel Lespinasse while (true) { 1640db4fbfb9SMichel Lespinasse struct rb_node *prev = &vma->vm_rb; 1641db4fbfb9SMichel Lespinasse if (!rb_parent(prev)) 1642db4fbfb9SMichel Lespinasse goto check_highest; 1643db4fbfb9SMichel Lespinasse vma = rb_entry(rb_parent(prev), 1644db4fbfb9SMichel Lespinasse struct vm_area_struct, vm_rb); 1645db4fbfb9SMichel Lespinasse if (prev == vma->vm_rb.rb_left) { 1646db4fbfb9SMichel Lespinasse gap_start = vma->vm_prev->vm_end; 1647db4fbfb9SMichel Lespinasse gap_end = vma->vm_start; 1648db4fbfb9SMichel Lespinasse goto check_current; 1649db4fbfb9SMichel Lespinasse } 1650db4fbfb9SMichel Lespinasse } 1651db4fbfb9SMichel Lespinasse } 1652db4fbfb9SMichel Lespinasse 1653db4fbfb9SMichel Lespinasse check_highest: 1654db4fbfb9SMichel Lespinasse /* Check highest gap, which does not precede any rbtree node */ 1655db4fbfb9SMichel Lespinasse gap_start = mm->highest_vm_end; 1656db4fbfb9SMichel Lespinasse gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */ 1657db4fbfb9SMichel Lespinasse if (gap_start > high_limit) 1658db4fbfb9SMichel Lespinasse return -ENOMEM; 1659db4fbfb9SMichel Lespinasse 1660db4fbfb9SMichel Lespinasse found: 1661db4fbfb9SMichel Lespinasse /* We found a suitable gap. Clip it with the original low_limit. */ 1662db4fbfb9SMichel Lespinasse if (gap_start < info->low_limit) 1663db4fbfb9SMichel Lespinasse gap_start = info->low_limit; 1664db4fbfb9SMichel Lespinasse 1665db4fbfb9SMichel Lespinasse /* Adjust gap address to the desired alignment */ 1666db4fbfb9SMichel Lespinasse gap_start += (info->align_offset - gap_start) & info->align_mask; 1667db4fbfb9SMichel Lespinasse 1668db4fbfb9SMichel Lespinasse VM_BUG_ON(gap_start + info->length > info->high_limit); 1669db4fbfb9SMichel Lespinasse VM_BUG_ON(gap_start + info->length > gap_end); 1670db4fbfb9SMichel Lespinasse return gap_start; 1671db4fbfb9SMichel Lespinasse } 1672db4fbfb9SMichel Lespinasse 1673db4fbfb9SMichel Lespinasse unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) 1674db4fbfb9SMichel Lespinasse { 1675db4fbfb9SMichel Lespinasse struct mm_struct *mm = current->mm; 1676db4fbfb9SMichel Lespinasse struct vm_area_struct *vma; 1677db4fbfb9SMichel Lespinasse unsigned long length, low_limit, high_limit, gap_start, gap_end; 1678db4fbfb9SMichel Lespinasse 1679db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1680db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1681db4fbfb9SMichel Lespinasse if (length < info->length) 1682db4fbfb9SMichel Lespinasse return -ENOMEM; 1683db4fbfb9SMichel Lespinasse 1684db4fbfb9SMichel Lespinasse /* 1685db4fbfb9SMichel Lespinasse * Adjust search limits by the desired length. 1686db4fbfb9SMichel Lespinasse * See implementation comment at top of unmapped_area(). 1687db4fbfb9SMichel Lespinasse */ 1688db4fbfb9SMichel Lespinasse gap_end = info->high_limit; 1689db4fbfb9SMichel Lespinasse if (gap_end < length) 1690db4fbfb9SMichel Lespinasse return -ENOMEM; 1691db4fbfb9SMichel Lespinasse high_limit = gap_end - length; 1692db4fbfb9SMichel Lespinasse 1693db4fbfb9SMichel Lespinasse if (info->low_limit > high_limit) 1694db4fbfb9SMichel Lespinasse return -ENOMEM; 1695db4fbfb9SMichel Lespinasse low_limit = info->low_limit + length; 1696db4fbfb9SMichel Lespinasse 1697db4fbfb9SMichel Lespinasse /* Check highest gap, which does not precede any rbtree node */ 1698db4fbfb9SMichel Lespinasse gap_start = mm->highest_vm_end; 1699db4fbfb9SMichel Lespinasse if (gap_start <= high_limit) 1700db4fbfb9SMichel Lespinasse goto found_highest; 1701db4fbfb9SMichel Lespinasse 1702db4fbfb9SMichel Lespinasse /* Check if rbtree root looks promising */ 1703db4fbfb9SMichel Lespinasse if (RB_EMPTY_ROOT(&mm->mm_rb)) 1704db4fbfb9SMichel Lespinasse return -ENOMEM; 1705db4fbfb9SMichel Lespinasse vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); 1706db4fbfb9SMichel Lespinasse if (vma->rb_subtree_gap < length) 1707db4fbfb9SMichel Lespinasse return -ENOMEM; 1708db4fbfb9SMichel Lespinasse 1709db4fbfb9SMichel Lespinasse while (true) { 1710db4fbfb9SMichel Lespinasse /* Visit right subtree if it looks promising */ 1711db4fbfb9SMichel Lespinasse gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; 1712db4fbfb9SMichel Lespinasse if (gap_start <= high_limit && vma->vm_rb.rb_right) { 1713db4fbfb9SMichel Lespinasse struct vm_area_struct *right = 1714db4fbfb9SMichel Lespinasse rb_entry(vma->vm_rb.rb_right, 1715db4fbfb9SMichel Lespinasse struct vm_area_struct, vm_rb); 1716db4fbfb9SMichel Lespinasse if (right->rb_subtree_gap >= length) { 1717db4fbfb9SMichel Lespinasse vma = right; 1718db4fbfb9SMichel Lespinasse continue; 1719db4fbfb9SMichel Lespinasse } 1720db4fbfb9SMichel Lespinasse } 1721db4fbfb9SMichel Lespinasse 1722db4fbfb9SMichel Lespinasse check_current: 1723db4fbfb9SMichel Lespinasse /* Check if current node has a suitable gap */ 1724db4fbfb9SMichel Lespinasse gap_end = vma->vm_start; 1725db4fbfb9SMichel Lespinasse if (gap_end < low_limit) 1726db4fbfb9SMichel Lespinasse return -ENOMEM; 1727db4fbfb9SMichel Lespinasse if (gap_start <= high_limit && gap_end - gap_start >= length) 1728db4fbfb9SMichel Lespinasse goto found; 1729db4fbfb9SMichel Lespinasse 1730db4fbfb9SMichel Lespinasse /* Visit left subtree if it looks promising */ 1731db4fbfb9SMichel Lespinasse if (vma->vm_rb.rb_left) { 1732db4fbfb9SMichel Lespinasse struct vm_area_struct *left = 1733db4fbfb9SMichel Lespinasse rb_entry(vma->vm_rb.rb_left, 1734db4fbfb9SMichel Lespinasse struct vm_area_struct, vm_rb); 1735db4fbfb9SMichel Lespinasse if (left->rb_subtree_gap >= length) { 1736db4fbfb9SMichel Lespinasse vma = left; 1737db4fbfb9SMichel Lespinasse continue; 1738db4fbfb9SMichel Lespinasse } 1739db4fbfb9SMichel Lespinasse } 1740db4fbfb9SMichel Lespinasse 1741db4fbfb9SMichel Lespinasse /* Go back up the rbtree to find next candidate node */ 1742db4fbfb9SMichel Lespinasse while (true) { 1743db4fbfb9SMichel Lespinasse struct rb_node *prev = &vma->vm_rb; 1744db4fbfb9SMichel Lespinasse if (!rb_parent(prev)) 1745db4fbfb9SMichel Lespinasse return -ENOMEM; 1746db4fbfb9SMichel Lespinasse vma = rb_entry(rb_parent(prev), 1747db4fbfb9SMichel Lespinasse struct vm_area_struct, vm_rb); 1748db4fbfb9SMichel Lespinasse if (prev == vma->vm_rb.rb_right) { 1749db4fbfb9SMichel Lespinasse gap_start = vma->vm_prev ? 1750db4fbfb9SMichel Lespinasse vma->vm_prev->vm_end : 0; 1751db4fbfb9SMichel Lespinasse goto check_current; 1752db4fbfb9SMichel Lespinasse } 1753db4fbfb9SMichel Lespinasse } 1754db4fbfb9SMichel Lespinasse } 1755db4fbfb9SMichel Lespinasse 1756db4fbfb9SMichel Lespinasse found: 1757db4fbfb9SMichel Lespinasse /* We found a suitable gap. Clip it with the original high_limit. */ 1758db4fbfb9SMichel Lespinasse if (gap_end > info->high_limit) 1759db4fbfb9SMichel Lespinasse gap_end = info->high_limit; 1760db4fbfb9SMichel Lespinasse 1761db4fbfb9SMichel Lespinasse found_highest: 1762db4fbfb9SMichel Lespinasse /* Compute highest gap address at the desired alignment */ 1763db4fbfb9SMichel Lespinasse gap_end -= info->length; 1764db4fbfb9SMichel Lespinasse gap_end -= (gap_end - info->align_offset) & info->align_mask; 1765db4fbfb9SMichel Lespinasse 1766db4fbfb9SMichel Lespinasse VM_BUG_ON(gap_end < info->low_limit); 1767db4fbfb9SMichel Lespinasse VM_BUG_ON(gap_end < gap_start); 1768db4fbfb9SMichel Lespinasse return gap_end; 1769db4fbfb9SMichel Lespinasse } 1770db4fbfb9SMichel Lespinasse 17711da177e4SLinus Torvalds /* Get an address range which is currently unmapped. 17721da177e4SLinus Torvalds * For shmat() with addr=0. 17731da177e4SLinus Torvalds * 17741da177e4SLinus Torvalds * Ugly calling convention alert: 17751da177e4SLinus Torvalds * Return value with the low bits set means error value, 17761da177e4SLinus Torvalds * ie 17771da177e4SLinus Torvalds * if (ret & ~PAGE_MASK) 17781da177e4SLinus Torvalds * error = ret; 17791da177e4SLinus Torvalds * 17801da177e4SLinus Torvalds * This function "knows" that -ENOMEM has the bits set. 17811da177e4SLinus Torvalds */ 17821da177e4SLinus Torvalds #ifndef HAVE_ARCH_UNMAPPED_AREA 17831da177e4SLinus Torvalds unsigned long 17841da177e4SLinus Torvalds arch_get_unmapped_area(struct file *filp, unsigned long addr, 17851da177e4SLinus Torvalds unsigned long len, unsigned long pgoff, unsigned long flags) 17861da177e4SLinus Torvalds { 17871da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 17881da177e4SLinus Torvalds struct vm_area_struct *vma; 1789db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 17901da177e4SLinus Torvalds 17911da177e4SLinus Torvalds if (len > TASK_SIZE) 17921da177e4SLinus Torvalds return -ENOMEM; 17931da177e4SLinus Torvalds 179406abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 179506abdfb4SBenjamin Herrenschmidt return addr; 179606abdfb4SBenjamin Herrenschmidt 17971da177e4SLinus Torvalds if (addr) { 17981da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 17991da177e4SLinus Torvalds vma = find_vma(mm, addr); 18001da177e4SLinus Torvalds if (TASK_SIZE - len >= addr && 18011da177e4SLinus Torvalds (!vma || addr + len <= vma->vm_start)) 18021da177e4SLinus Torvalds return addr; 18031da177e4SLinus Torvalds } 18041da177e4SLinus Torvalds 1805db4fbfb9SMichel Lespinasse info.flags = 0; 1806db4fbfb9SMichel Lespinasse info.length = len; 1807db4fbfb9SMichel Lespinasse info.low_limit = TASK_UNMAPPED_BASE; 1808db4fbfb9SMichel Lespinasse info.high_limit = TASK_SIZE; 1809db4fbfb9SMichel Lespinasse info.align_mask = 0; 1810db4fbfb9SMichel Lespinasse return vm_unmapped_area(&info); 18111da177e4SLinus Torvalds } 18121da177e4SLinus Torvalds #endif 18131da177e4SLinus Torvalds 18141363c3cdSWolfgang Wander void arch_unmap_area(struct mm_struct *mm, unsigned long addr) 18151da177e4SLinus Torvalds { 18161da177e4SLinus Torvalds /* 18171da177e4SLinus Torvalds * Is this a new hole at the lowest possible address? 18181da177e4SLinus Torvalds */ 1819f44d2198SXiao Guangrong if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) 18201363c3cdSWolfgang Wander mm->free_area_cache = addr; 18211da177e4SLinus Torvalds } 18221da177e4SLinus Torvalds 18231da177e4SLinus Torvalds /* 18241da177e4SLinus Torvalds * This mmap-allocator allocates new areas top-down from below the 18251da177e4SLinus Torvalds * stack's low limit (the base): 18261da177e4SLinus Torvalds */ 18271da177e4SLinus Torvalds #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN 18281da177e4SLinus Torvalds unsigned long 18291da177e4SLinus Torvalds arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 18301da177e4SLinus Torvalds const unsigned long len, const unsigned long pgoff, 18311da177e4SLinus Torvalds const unsigned long flags) 18321da177e4SLinus Torvalds { 18331da177e4SLinus Torvalds struct vm_area_struct *vma; 18341da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1835db4fbfb9SMichel Lespinasse unsigned long addr = addr0; 1836db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 18371da177e4SLinus Torvalds 18381da177e4SLinus Torvalds /* requested length too big for entire address space */ 18391da177e4SLinus Torvalds if (len > TASK_SIZE) 18401da177e4SLinus Torvalds return -ENOMEM; 18411da177e4SLinus Torvalds 184206abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 184306abdfb4SBenjamin Herrenschmidt return addr; 184406abdfb4SBenjamin Herrenschmidt 18451da177e4SLinus Torvalds /* requesting a specific address */ 18461da177e4SLinus Torvalds if (addr) { 18471da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 18481da177e4SLinus Torvalds vma = find_vma(mm, addr); 18491da177e4SLinus Torvalds if (TASK_SIZE - len >= addr && 18501da177e4SLinus Torvalds (!vma || addr + len <= vma->vm_start)) 18511da177e4SLinus Torvalds return addr; 18521da177e4SLinus Torvalds } 18531da177e4SLinus Torvalds 1854db4fbfb9SMichel Lespinasse info.flags = VM_UNMAPPED_AREA_TOPDOWN; 1855db4fbfb9SMichel Lespinasse info.length = len; 1856db4fbfb9SMichel Lespinasse info.low_limit = PAGE_SIZE; 1857db4fbfb9SMichel Lespinasse info.high_limit = mm->mmap_base; 1858db4fbfb9SMichel Lespinasse info.align_mask = 0; 1859db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1860b716ad95SXiao Guangrong 18611da177e4SLinus Torvalds /* 18621da177e4SLinus Torvalds * A failed mmap() very likely causes application failure, 18631da177e4SLinus Torvalds * so fall back to the bottom-up function here. This scenario 18641da177e4SLinus Torvalds * can happen with large stack limits and large mmap() 18651da177e4SLinus Torvalds * allocations. 18661da177e4SLinus Torvalds */ 1867db4fbfb9SMichel Lespinasse if (addr & ~PAGE_MASK) { 1868db4fbfb9SMichel Lespinasse VM_BUG_ON(addr != -ENOMEM); 1869db4fbfb9SMichel Lespinasse info.flags = 0; 1870db4fbfb9SMichel Lespinasse info.low_limit = TASK_UNMAPPED_BASE; 1871db4fbfb9SMichel Lespinasse info.high_limit = TASK_SIZE; 1872db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1873db4fbfb9SMichel Lespinasse } 18741da177e4SLinus Torvalds 18751da177e4SLinus Torvalds return addr; 18761da177e4SLinus Torvalds } 18771da177e4SLinus Torvalds #endif 18781da177e4SLinus Torvalds 18791363c3cdSWolfgang Wander void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr) 18801da177e4SLinus Torvalds { 18811da177e4SLinus Torvalds /* 18821da177e4SLinus Torvalds * Is this a new hole at the highest possible address? 18831da177e4SLinus Torvalds */ 18841363c3cdSWolfgang Wander if (addr > mm->free_area_cache) 18851363c3cdSWolfgang Wander mm->free_area_cache = addr; 18861da177e4SLinus Torvalds 18871da177e4SLinus Torvalds /* dont allow allocations above current base */ 18881363c3cdSWolfgang Wander if (mm->free_area_cache > mm->mmap_base) 18891363c3cdSWolfgang Wander mm->free_area_cache = mm->mmap_base; 18901da177e4SLinus Torvalds } 18911da177e4SLinus Torvalds 18921da177e4SLinus Torvalds unsigned long 18931da177e4SLinus Torvalds get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, 18941da177e4SLinus Torvalds unsigned long pgoff, unsigned long flags) 18951da177e4SLinus Torvalds { 189606abdfb4SBenjamin Herrenschmidt unsigned long (*get_area)(struct file *, unsigned long, 189706abdfb4SBenjamin Herrenschmidt unsigned long, unsigned long, unsigned long); 189807ab67c8SLinus Torvalds 18999206de95SAl Viro unsigned long error = arch_mmap_check(addr, len, flags); 19009206de95SAl Viro if (error) 19019206de95SAl Viro return error; 19029206de95SAl Viro 19039206de95SAl Viro /* Careful about overflows.. */ 19049206de95SAl Viro if (len > TASK_SIZE) 19059206de95SAl Viro return -ENOMEM; 19069206de95SAl Viro 190707ab67c8SLinus Torvalds get_area = current->mm->get_unmapped_area; 190807ab67c8SLinus Torvalds if (file && file->f_op && file->f_op->get_unmapped_area) 190907ab67c8SLinus Torvalds get_area = file->f_op->get_unmapped_area; 191007ab67c8SLinus Torvalds addr = get_area(file, addr, len, pgoff, flags); 191107ab67c8SLinus Torvalds if (IS_ERR_VALUE(addr)) 191207ab67c8SLinus Torvalds return addr; 191307ab67c8SLinus Torvalds 19141da177e4SLinus Torvalds if (addr > TASK_SIZE - len) 19151da177e4SLinus Torvalds return -ENOMEM; 19161da177e4SLinus Torvalds if (addr & ~PAGE_MASK) 19171da177e4SLinus Torvalds return -EINVAL; 191806abdfb4SBenjamin Herrenschmidt 19199ac4ed4bSAl Viro addr = arch_rebalance_pgtables(addr, len); 19209ac4ed4bSAl Viro error = security_mmap_addr(addr); 19219ac4ed4bSAl Viro return error ? error : addr; 19221da177e4SLinus Torvalds } 19231da177e4SLinus Torvalds 19241da177e4SLinus Torvalds EXPORT_SYMBOL(get_unmapped_area); 19251da177e4SLinus Torvalds 19261da177e4SLinus Torvalds /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ 19271da177e4SLinus Torvalds struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) 19281da177e4SLinus Torvalds { 19291da177e4SLinus Torvalds struct vm_area_struct *vma = NULL; 19301da177e4SLinus Torvalds 1931841e31e5SRajman Mekaco if (WARN_ON_ONCE(!mm)) /* Remove this in linux-3.6 */ 1932841e31e5SRajman Mekaco return NULL; 1933841e31e5SRajman Mekaco 19341da177e4SLinus Torvalds /* Check the cache first. */ 19351da177e4SLinus Torvalds /* (Cache hit rate is typically around 35%.) */ 19361da177e4SLinus Torvalds vma = mm->mmap_cache; 19371da177e4SLinus Torvalds if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { 19381da177e4SLinus Torvalds struct rb_node *rb_node; 19391da177e4SLinus Torvalds 19401da177e4SLinus Torvalds rb_node = mm->mm_rb.rb_node; 19411da177e4SLinus Torvalds vma = NULL; 19421da177e4SLinus Torvalds 19431da177e4SLinus Torvalds while (rb_node) { 19441da177e4SLinus Torvalds struct vm_area_struct *vma_tmp; 19451da177e4SLinus Torvalds 19461da177e4SLinus Torvalds vma_tmp = rb_entry(rb_node, 19471da177e4SLinus Torvalds struct vm_area_struct, vm_rb); 19481da177e4SLinus Torvalds 19491da177e4SLinus Torvalds if (vma_tmp->vm_end > addr) { 19501da177e4SLinus Torvalds vma = vma_tmp; 19511da177e4SLinus Torvalds if (vma_tmp->vm_start <= addr) 19521da177e4SLinus Torvalds break; 19531da177e4SLinus Torvalds rb_node = rb_node->rb_left; 19541da177e4SLinus Torvalds } else 19551da177e4SLinus Torvalds rb_node = rb_node->rb_right; 19561da177e4SLinus Torvalds } 19571da177e4SLinus Torvalds if (vma) 19581da177e4SLinus Torvalds mm->mmap_cache = vma; 19591da177e4SLinus Torvalds } 19601da177e4SLinus Torvalds return vma; 19611da177e4SLinus Torvalds } 19621da177e4SLinus Torvalds 19631da177e4SLinus Torvalds EXPORT_SYMBOL(find_vma); 19641da177e4SLinus Torvalds 19656bd4837dSKOSAKI Motohiro /* 19666bd4837dSKOSAKI Motohiro * Same as find_vma, but also return a pointer to the previous VMA in *pprev. 19676bd4837dSKOSAKI Motohiro */ 19681da177e4SLinus Torvalds struct vm_area_struct * 19691da177e4SLinus Torvalds find_vma_prev(struct mm_struct *mm, unsigned long addr, 19701da177e4SLinus Torvalds struct vm_area_struct **pprev) 19711da177e4SLinus Torvalds { 19726bd4837dSKOSAKI Motohiro struct vm_area_struct *vma; 19731da177e4SLinus Torvalds 19746bd4837dSKOSAKI Motohiro vma = find_vma(mm, addr); 197583cd904dSMikulas Patocka if (vma) { 197683cd904dSMikulas Patocka *pprev = vma->vm_prev; 197783cd904dSMikulas Patocka } else { 197883cd904dSMikulas Patocka struct rb_node *rb_node = mm->mm_rb.rb_node; 197983cd904dSMikulas Patocka *pprev = NULL; 198083cd904dSMikulas Patocka while (rb_node) { 198183cd904dSMikulas Patocka *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb); 198283cd904dSMikulas Patocka rb_node = rb_node->rb_right; 198383cd904dSMikulas Patocka } 198483cd904dSMikulas Patocka } 19856bd4837dSKOSAKI Motohiro return vma; 19861da177e4SLinus Torvalds } 19871da177e4SLinus Torvalds 19881da177e4SLinus Torvalds /* 19891da177e4SLinus Torvalds * Verify that the stack growth is acceptable and 19901da177e4SLinus Torvalds * update accounting. This is shared with both the 19911da177e4SLinus Torvalds * grow-up and grow-down cases. 19921da177e4SLinus Torvalds */ 19931da177e4SLinus Torvalds static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow) 19941da177e4SLinus Torvalds { 19951da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 19961da177e4SLinus Torvalds struct rlimit *rlim = current->signal->rlim; 19970d59a01bSAdam Litke unsigned long new_start; 19981da177e4SLinus Torvalds 19991da177e4SLinus Torvalds /* address space limit tests */ 2000119f657cSakpm@osdl.org if (!may_expand_vm(mm, grow)) 20011da177e4SLinus Torvalds return -ENOMEM; 20021da177e4SLinus Torvalds 20031da177e4SLinus Torvalds /* Stack limit test */ 200459e99e5bSJiri Slaby if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur)) 20051da177e4SLinus Torvalds return -ENOMEM; 20061da177e4SLinus Torvalds 20071da177e4SLinus Torvalds /* mlock limit tests */ 20081da177e4SLinus Torvalds if (vma->vm_flags & VM_LOCKED) { 20091da177e4SLinus Torvalds unsigned long locked; 20101da177e4SLinus Torvalds unsigned long limit; 20111da177e4SLinus Torvalds locked = mm->locked_vm + grow; 201259e99e5bSJiri Slaby limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur); 201359e99e5bSJiri Slaby limit >>= PAGE_SHIFT; 20141da177e4SLinus Torvalds if (locked > limit && !capable(CAP_IPC_LOCK)) 20151da177e4SLinus Torvalds return -ENOMEM; 20161da177e4SLinus Torvalds } 20171da177e4SLinus Torvalds 20180d59a01bSAdam Litke /* Check to ensure the stack will not grow into a hugetlb-only region */ 20190d59a01bSAdam Litke new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : 20200d59a01bSAdam Litke vma->vm_end - size; 20210d59a01bSAdam Litke if (is_hugepage_only_range(vma->vm_mm, new_start, size)) 20220d59a01bSAdam Litke return -EFAULT; 20230d59a01bSAdam Litke 20241da177e4SLinus Torvalds /* 20251da177e4SLinus Torvalds * Overcommit.. This must be the final test, as it will 20261da177e4SLinus Torvalds * update security statistics. 20271da177e4SLinus Torvalds */ 202805fa199dSHugh Dickins if (security_vm_enough_memory_mm(mm, grow)) 20291da177e4SLinus Torvalds return -ENOMEM; 20301da177e4SLinus Torvalds 20311da177e4SLinus Torvalds /* Ok, everything looks good - let it rip */ 20321da177e4SLinus Torvalds if (vma->vm_flags & VM_LOCKED) 20331da177e4SLinus Torvalds mm->locked_vm += grow; 2034ab50b8edSHugh Dickins vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); 20351da177e4SLinus Torvalds return 0; 20361da177e4SLinus Torvalds } 20371da177e4SLinus Torvalds 203846dea3d0SHugh Dickins #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) 20391da177e4SLinus Torvalds /* 204046dea3d0SHugh Dickins * PA-RISC uses this for its stack; IA64 for its Register Backing Store. 204146dea3d0SHugh Dickins * vma is the last one with address > vma->vm_end. Have to extend vma. 20421da177e4SLinus Torvalds */ 204346dea3d0SHugh Dickins int expand_upwards(struct vm_area_struct *vma, unsigned long address) 20441da177e4SLinus Torvalds { 20451da177e4SLinus Torvalds int error; 20461da177e4SLinus Torvalds 20471da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSUP)) 20481da177e4SLinus Torvalds return -EFAULT; 20491da177e4SLinus Torvalds 20501da177e4SLinus Torvalds /* 20511da177e4SLinus Torvalds * We must make sure the anon_vma is allocated 20521da177e4SLinus Torvalds * so that the anon_vma locking is not a noop. 20531da177e4SLinus Torvalds */ 20541da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 20551da177e4SLinus Torvalds return -ENOMEM; 2056bb4a340eSRik van Riel vma_lock_anon_vma(vma); 20571da177e4SLinus Torvalds 20581da177e4SLinus Torvalds /* 20591da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 20601da177e4SLinus Torvalds * is required to hold the mmap_sem in read mode. We need the 20611da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 206206b32f3aSHelge Deller * Also guard against wrapping around to address 0. 20631da177e4SLinus Torvalds */ 206406b32f3aSHelge Deller if (address < PAGE_ALIGN(address+4)) 206506b32f3aSHelge Deller address = PAGE_ALIGN(address+4); 206606b32f3aSHelge Deller else { 2067bb4a340eSRik van Riel vma_unlock_anon_vma(vma); 206806b32f3aSHelge Deller return -ENOMEM; 206906b32f3aSHelge Deller } 20701da177e4SLinus Torvalds error = 0; 20711da177e4SLinus Torvalds 20721da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 20731da177e4SLinus Torvalds if (address > vma->vm_end) { 20741da177e4SLinus Torvalds unsigned long size, grow; 20751da177e4SLinus Torvalds 20761da177e4SLinus Torvalds size = address - vma->vm_start; 20771da177e4SLinus Torvalds grow = (address - vma->vm_end) >> PAGE_SHIFT; 20781da177e4SLinus Torvalds 207942c36f63SHugh Dickins error = -ENOMEM; 208042c36f63SHugh Dickins if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { 20811da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 20823af9e859SEric B Munson if (!error) { 20834128997bSMichel Lespinasse /* 20844128997bSMichel Lespinasse * vma_gap_update() doesn't support concurrent 20854128997bSMichel Lespinasse * updates, but we only hold a shared mmap_sem 20864128997bSMichel Lespinasse * lock here, so we need to protect against 20874128997bSMichel Lespinasse * concurrent vma expansions. 20884128997bSMichel Lespinasse * vma_lock_anon_vma() doesn't help here, as 20894128997bSMichel Lespinasse * we don't guarantee that all growable vmas 20904128997bSMichel Lespinasse * in a mm share the same root anon vma. 20914128997bSMichel Lespinasse * So, we reuse mm->page_table_lock to guard 20924128997bSMichel Lespinasse * against concurrent vma expansions. 20934128997bSMichel Lespinasse */ 20944128997bSMichel Lespinasse spin_lock(&vma->vm_mm->page_table_lock); 2095bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 20961da177e4SLinus Torvalds vma->vm_end = address; 2097bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 2098d3737187SMichel Lespinasse if (vma->vm_next) 2099d3737187SMichel Lespinasse vma_gap_update(vma->vm_next); 2100d3737187SMichel Lespinasse else 2101d3737187SMichel Lespinasse vma->vm_mm->highest_vm_end = address; 21024128997bSMichel Lespinasse spin_unlock(&vma->vm_mm->page_table_lock); 21034128997bSMichel Lespinasse 21043af9e859SEric B Munson perf_event_mmap(vma); 21053af9e859SEric B Munson } 21061da177e4SLinus Torvalds } 210742c36f63SHugh Dickins } 2108bb4a340eSRik van Riel vma_unlock_anon_vma(vma); 2109b15d00b6SAndrea Arcangeli khugepaged_enter_vma_merge(vma); 2110ed8ea815SMichel Lespinasse validate_mm(vma->vm_mm); 21111da177e4SLinus Torvalds return error; 21121da177e4SLinus Torvalds } 211346dea3d0SHugh Dickins #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ 211446dea3d0SHugh Dickins 21151da177e4SLinus Torvalds /* 21161da177e4SLinus Torvalds * vma is the first one with address < vma->vm_start. Have to extend vma. 21171da177e4SLinus Torvalds */ 2118d05f3169SMichal Hocko int expand_downwards(struct vm_area_struct *vma, 2119b6a2fea3SOllie Wild unsigned long address) 21201da177e4SLinus Torvalds { 21211da177e4SLinus Torvalds int error; 21221da177e4SLinus Torvalds 21231da177e4SLinus Torvalds /* 21241da177e4SLinus Torvalds * We must make sure the anon_vma is allocated 21251da177e4SLinus Torvalds * so that the anon_vma locking is not a noop. 21261da177e4SLinus Torvalds */ 21271da177e4SLinus Torvalds if (unlikely(anon_vma_prepare(vma))) 21281da177e4SLinus Torvalds return -ENOMEM; 21298869477aSEric Paris 21308869477aSEric Paris address &= PAGE_MASK; 2131e5467859SAl Viro error = security_mmap_addr(address); 21328869477aSEric Paris if (error) 21338869477aSEric Paris return error; 21348869477aSEric Paris 2135bb4a340eSRik van Riel vma_lock_anon_vma(vma); 21361da177e4SLinus Torvalds 21371da177e4SLinus Torvalds /* 21381da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 21391da177e4SLinus Torvalds * is required to hold the mmap_sem in read mode. We need the 21401da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 21411da177e4SLinus Torvalds */ 21421da177e4SLinus Torvalds 21431da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 21441da177e4SLinus Torvalds if (address < vma->vm_start) { 21451da177e4SLinus Torvalds unsigned long size, grow; 21461da177e4SLinus Torvalds 21471da177e4SLinus Torvalds size = vma->vm_end - address; 21481da177e4SLinus Torvalds grow = (vma->vm_start - address) >> PAGE_SHIFT; 21491da177e4SLinus Torvalds 2150a626ca6aSLinus Torvalds error = -ENOMEM; 2151a626ca6aSLinus Torvalds if (grow <= vma->vm_pgoff) { 21521da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 21531da177e4SLinus Torvalds if (!error) { 21544128997bSMichel Lespinasse /* 21554128997bSMichel Lespinasse * vma_gap_update() doesn't support concurrent 21564128997bSMichel Lespinasse * updates, but we only hold a shared mmap_sem 21574128997bSMichel Lespinasse * lock here, so we need to protect against 21584128997bSMichel Lespinasse * concurrent vma expansions. 21594128997bSMichel Lespinasse * vma_lock_anon_vma() doesn't help here, as 21604128997bSMichel Lespinasse * we don't guarantee that all growable vmas 21614128997bSMichel Lespinasse * in a mm share the same root anon vma. 21624128997bSMichel Lespinasse * So, we reuse mm->page_table_lock to guard 21634128997bSMichel Lespinasse * against concurrent vma expansions. 21644128997bSMichel Lespinasse */ 21654128997bSMichel Lespinasse spin_lock(&vma->vm_mm->page_table_lock); 2166bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 21671da177e4SLinus Torvalds vma->vm_start = address; 21681da177e4SLinus Torvalds vma->vm_pgoff -= grow; 2169bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 2170d3737187SMichel Lespinasse vma_gap_update(vma); 21714128997bSMichel Lespinasse spin_unlock(&vma->vm_mm->page_table_lock); 21724128997bSMichel Lespinasse 21733af9e859SEric B Munson perf_event_mmap(vma); 21741da177e4SLinus Torvalds } 21751da177e4SLinus Torvalds } 2176a626ca6aSLinus Torvalds } 2177bb4a340eSRik van Riel vma_unlock_anon_vma(vma); 2178b15d00b6SAndrea Arcangeli khugepaged_enter_vma_merge(vma); 2179ed8ea815SMichel Lespinasse validate_mm(vma->vm_mm); 21801da177e4SLinus Torvalds return error; 21811da177e4SLinus Torvalds } 21821da177e4SLinus Torvalds 2183b6a2fea3SOllie Wild #ifdef CONFIG_STACK_GROWSUP 2184b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2185b6a2fea3SOllie Wild { 2186b6a2fea3SOllie Wild return expand_upwards(vma, address); 2187b6a2fea3SOllie Wild } 2188b6a2fea3SOllie Wild 2189b6a2fea3SOllie Wild struct vm_area_struct * 2190b6a2fea3SOllie Wild find_extend_vma(struct mm_struct *mm, unsigned long addr) 2191b6a2fea3SOllie Wild { 2192b6a2fea3SOllie Wild struct vm_area_struct *vma, *prev; 2193b6a2fea3SOllie Wild 2194b6a2fea3SOllie Wild addr &= PAGE_MASK; 2195b6a2fea3SOllie Wild vma = find_vma_prev(mm, addr, &prev); 2196b6a2fea3SOllie Wild if (vma && (vma->vm_start <= addr)) 2197b6a2fea3SOllie Wild return vma; 21981c127185SDenys Vlasenko if (!prev || expand_stack(prev, addr)) 2199b6a2fea3SOllie Wild return NULL; 2200ba470de4SRik van Riel if (prev->vm_flags & VM_LOCKED) { 2201c58267c3SKOSAKI Motohiro mlock_vma_pages_range(prev, addr, prev->vm_end); 2202ba470de4SRik van Riel } 2203b6a2fea3SOllie Wild return prev; 2204b6a2fea3SOllie Wild } 2205b6a2fea3SOllie Wild #else 2206b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2207b6a2fea3SOllie Wild { 2208b6a2fea3SOllie Wild return expand_downwards(vma, address); 2209b6a2fea3SOllie Wild } 2210b6a2fea3SOllie Wild 22111da177e4SLinus Torvalds struct vm_area_struct * 22121da177e4SLinus Torvalds find_extend_vma(struct mm_struct * mm, unsigned long addr) 22131da177e4SLinus Torvalds { 22141da177e4SLinus Torvalds struct vm_area_struct * vma; 22151da177e4SLinus Torvalds unsigned long start; 22161da177e4SLinus Torvalds 22171da177e4SLinus Torvalds addr &= PAGE_MASK; 22181da177e4SLinus Torvalds vma = find_vma(mm,addr); 22191da177e4SLinus Torvalds if (!vma) 22201da177e4SLinus Torvalds return NULL; 22211da177e4SLinus Torvalds if (vma->vm_start <= addr) 22221da177e4SLinus Torvalds return vma; 22231da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 22241da177e4SLinus Torvalds return NULL; 22251da177e4SLinus Torvalds start = vma->vm_start; 22261da177e4SLinus Torvalds if (expand_stack(vma, addr)) 22271da177e4SLinus Torvalds return NULL; 2228ba470de4SRik van Riel if (vma->vm_flags & VM_LOCKED) { 2229c58267c3SKOSAKI Motohiro mlock_vma_pages_range(vma, addr, start); 2230ba470de4SRik van Riel } 22311da177e4SLinus Torvalds return vma; 22321da177e4SLinus Torvalds } 22331da177e4SLinus Torvalds #endif 22341da177e4SLinus Torvalds 22352c0b3814SHugh Dickins /* 22362c0b3814SHugh Dickins * Ok - we have the memory areas we should free on the vma list, 22372c0b3814SHugh Dickins * so release them, and do the vma updates. 22381da177e4SLinus Torvalds * 22392c0b3814SHugh Dickins * Called with the mm semaphore held. 22401da177e4SLinus Torvalds */ 22412c0b3814SHugh Dickins static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) 22421da177e4SLinus Torvalds { 22434f74d2c8SLinus Torvalds unsigned long nr_accounted = 0; 22444f74d2c8SLinus Torvalds 2245365e9c87SHugh Dickins /* Update high watermark before we lower total_vm */ 2246365e9c87SHugh Dickins update_hiwater_vm(mm); 22472c0b3814SHugh Dickins do { 2248ab50b8edSHugh Dickins long nrpages = vma_pages(vma); 22491da177e4SLinus Torvalds 22504f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 22514f74d2c8SLinus Torvalds nr_accounted += nrpages; 2252ab50b8edSHugh Dickins vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); 2253a8fb5618SHugh Dickins vma = remove_vma(vma); 2254146425a3SHugh Dickins } while (vma); 22554f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 22561da177e4SLinus Torvalds validate_mm(mm); 22571da177e4SLinus Torvalds } 22581da177e4SLinus Torvalds 22591da177e4SLinus Torvalds /* 22601da177e4SLinus Torvalds * Get rid of page table information in the indicated region. 22611da177e4SLinus Torvalds * 2262f10df686SPaolo 'Blaisorblade' Giarrusso * Called with the mm semaphore held. 22631da177e4SLinus Torvalds */ 22641da177e4SLinus Torvalds static void unmap_region(struct mm_struct *mm, 2265e0da382cSHugh Dickins struct vm_area_struct *vma, struct vm_area_struct *prev, 2266e0da382cSHugh Dickins unsigned long start, unsigned long end) 22671da177e4SLinus Torvalds { 2268e0da382cSHugh Dickins struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; 2269d16dfc55SPeter Zijlstra struct mmu_gather tlb; 22701da177e4SLinus Torvalds 22711da177e4SLinus Torvalds lru_add_drain(); 2272d16dfc55SPeter Zijlstra tlb_gather_mmu(&tlb, mm, 0); 2273365e9c87SHugh Dickins update_hiwater_rss(mm); 22744f74d2c8SLinus Torvalds unmap_vmas(&tlb, vma, start, end); 2275d16dfc55SPeter Zijlstra free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, 2276e0da382cSHugh Dickins next ? next->vm_start : 0); 2277d16dfc55SPeter Zijlstra tlb_finish_mmu(&tlb, start, end); 22781da177e4SLinus Torvalds } 22791da177e4SLinus Torvalds 22801da177e4SLinus Torvalds /* 22811da177e4SLinus Torvalds * Create a list of vma's touched by the unmap, removing them from the mm's 22821da177e4SLinus Torvalds * vma list as we go.. 22831da177e4SLinus Torvalds */ 22841da177e4SLinus Torvalds static void 22851da177e4SLinus Torvalds detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, 22861da177e4SLinus Torvalds struct vm_area_struct *prev, unsigned long end) 22871da177e4SLinus Torvalds { 22881da177e4SLinus Torvalds struct vm_area_struct **insertion_point; 22891da177e4SLinus Torvalds struct vm_area_struct *tail_vma = NULL; 22901363c3cdSWolfgang Wander unsigned long addr; 22911da177e4SLinus Torvalds 22921da177e4SLinus Torvalds insertion_point = (prev ? &prev->vm_next : &mm->mmap); 2293297c5eeeSLinus Torvalds vma->vm_prev = NULL; 22941da177e4SLinus Torvalds do { 2295d3737187SMichel Lespinasse vma_rb_erase(vma, &mm->mm_rb); 22961da177e4SLinus Torvalds mm->map_count--; 22971da177e4SLinus Torvalds tail_vma = vma; 22981da177e4SLinus Torvalds vma = vma->vm_next; 22991da177e4SLinus Torvalds } while (vma && vma->vm_start < end); 23001da177e4SLinus Torvalds *insertion_point = vma; 2301d3737187SMichel Lespinasse if (vma) { 2302297c5eeeSLinus Torvalds vma->vm_prev = prev; 2303d3737187SMichel Lespinasse vma_gap_update(vma); 2304d3737187SMichel Lespinasse } else 2305d3737187SMichel Lespinasse mm->highest_vm_end = prev ? prev->vm_end : 0; 23061da177e4SLinus Torvalds tail_vma->vm_next = NULL; 23071363c3cdSWolfgang Wander if (mm->unmap_area == arch_unmap_area) 23081363c3cdSWolfgang Wander addr = prev ? prev->vm_end : mm->mmap_base; 23091363c3cdSWolfgang Wander else 23101363c3cdSWolfgang Wander addr = vma ? vma->vm_start : mm->mmap_base; 23111363c3cdSWolfgang Wander mm->unmap_area(mm, addr); 23121da177e4SLinus Torvalds mm->mmap_cache = NULL; /* Kill the cache. */ 23131da177e4SLinus Torvalds } 23141da177e4SLinus Torvalds 23151da177e4SLinus Torvalds /* 2316659ace58SKOSAKI Motohiro * __split_vma() bypasses sysctl_max_map_count checking. We use this on the 2317659ace58SKOSAKI Motohiro * munmap path where it doesn't make sense to fail. 23181da177e4SLinus Torvalds */ 2319659ace58SKOSAKI Motohiro static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, 23201da177e4SLinus Torvalds unsigned long addr, int new_below) 23211da177e4SLinus Torvalds { 23221da177e4SLinus Torvalds struct mempolicy *pol; 23231da177e4SLinus Torvalds struct vm_area_struct *new; 23245beb4930SRik van Riel int err = -ENOMEM; 23251da177e4SLinus Torvalds 2326a5516438SAndi Kleen if (is_vm_hugetlb_page(vma) && (addr & 2327a5516438SAndi Kleen ~(huge_page_mask(hstate_vma(vma))))) 23281da177e4SLinus Torvalds return -EINVAL; 23291da177e4SLinus Torvalds 2330e94b1766SChristoph Lameter new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); 23311da177e4SLinus Torvalds if (!new) 23325beb4930SRik van Riel goto out_err; 23331da177e4SLinus Torvalds 23341da177e4SLinus Torvalds /* most fields are the same, copy all, and then fixup */ 23351da177e4SLinus Torvalds *new = *vma; 23361da177e4SLinus Torvalds 23375beb4930SRik van Riel INIT_LIST_HEAD(&new->anon_vma_chain); 23385beb4930SRik van Riel 23391da177e4SLinus Torvalds if (new_below) 23401da177e4SLinus Torvalds new->vm_end = addr; 23411da177e4SLinus Torvalds else { 23421da177e4SLinus Torvalds new->vm_start = addr; 23431da177e4SLinus Torvalds new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); 23441da177e4SLinus Torvalds } 23451da177e4SLinus Torvalds 2346846a16bfSLee Schermerhorn pol = mpol_dup(vma_policy(vma)); 23471da177e4SLinus Torvalds if (IS_ERR(pol)) { 23485beb4930SRik van Riel err = PTR_ERR(pol); 23495beb4930SRik van Riel goto out_free_vma; 23501da177e4SLinus Torvalds } 23511da177e4SLinus Torvalds vma_set_policy(new, pol); 23521da177e4SLinus Torvalds 23535beb4930SRik van Riel if (anon_vma_clone(new, vma)) 23545beb4930SRik van Riel goto out_free_mpol; 23555beb4930SRik van Riel 2356e9714acfSKonstantin Khlebnikov if (new->vm_file) 23571da177e4SLinus Torvalds get_file(new->vm_file); 23581da177e4SLinus Torvalds 23591da177e4SLinus Torvalds if (new->vm_ops && new->vm_ops->open) 23601da177e4SLinus Torvalds new->vm_ops->open(new); 23611da177e4SLinus Torvalds 23621da177e4SLinus Torvalds if (new_below) 23635beb4930SRik van Riel err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + 23641da177e4SLinus Torvalds ((addr - new->vm_start) >> PAGE_SHIFT), new); 23651da177e4SLinus Torvalds else 23665beb4930SRik van Riel err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); 23671da177e4SLinus Torvalds 23685beb4930SRik van Riel /* Success. */ 23695beb4930SRik van Riel if (!err) 23701da177e4SLinus Torvalds return 0; 23715beb4930SRik van Riel 23725beb4930SRik van Riel /* Clean everything up if vma_adjust failed. */ 237358927533SRik van Riel if (new->vm_ops && new->vm_ops->close) 23745beb4930SRik van Riel new->vm_ops->close(new); 2375e9714acfSKonstantin Khlebnikov if (new->vm_file) 23765beb4930SRik van Riel fput(new->vm_file); 23772aeadc30SAndrea Arcangeli unlink_anon_vmas(new); 23785beb4930SRik van Riel out_free_mpol: 23795beb4930SRik van Riel mpol_put(pol); 23805beb4930SRik van Riel out_free_vma: 23815beb4930SRik van Riel kmem_cache_free(vm_area_cachep, new); 23825beb4930SRik van Riel out_err: 23835beb4930SRik van Riel return err; 23841da177e4SLinus Torvalds } 23851da177e4SLinus Torvalds 2386659ace58SKOSAKI Motohiro /* 2387659ace58SKOSAKI Motohiro * Split a vma into two pieces at address 'addr', a new vma is allocated 2388659ace58SKOSAKI Motohiro * either for the first part or the tail. 2389659ace58SKOSAKI Motohiro */ 2390659ace58SKOSAKI Motohiro int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, 2391659ace58SKOSAKI Motohiro unsigned long addr, int new_below) 2392659ace58SKOSAKI Motohiro { 2393659ace58SKOSAKI Motohiro if (mm->map_count >= sysctl_max_map_count) 2394659ace58SKOSAKI Motohiro return -ENOMEM; 2395659ace58SKOSAKI Motohiro 2396659ace58SKOSAKI Motohiro return __split_vma(mm, vma, addr, new_below); 2397659ace58SKOSAKI Motohiro } 2398659ace58SKOSAKI Motohiro 23991da177e4SLinus Torvalds /* Munmap is split into 2 main parts -- this part which finds 24001da177e4SLinus Torvalds * what needs doing, and the areas themselves, which do the 24011da177e4SLinus Torvalds * work. This now handles partial unmappings. 24021da177e4SLinus Torvalds * Jeremy Fitzhardinge <jeremy@goop.org> 24031da177e4SLinus Torvalds */ 24041da177e4SLinus Torvalds int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) 24051da177e4SLinus Torvalds { 24061da177e4SLinus Torvalds unsigned long end; 2407146425a3SHugh Dickins struct vm_area_struct *vma, *prev, *last; 24081da177e4SLinus Torvalds 24091da177e4SLinus Torvalds if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start) 24101da177e4SLinus Torvalds return -EINVAL; 24111da177e4SLinus Torvalds 24121da177e4SLinus Torvalds if ((len = PAGE_ALIGN(len)) == 0) 24131da177e4SLinus Torvalds return -EINVAL; 24141da177e4SLinus Torvalds 24151da177e4SLinus Torvalds /* Find the first overlapping VMA */ 24169be34c9dSLinus Torvalds vma = find_vma(mm, start); 2417146425a3SHugh Dickins if (!vma) 24181da177e4SLinus Torvalds return 0; 24199be34c9dSLinus Torvalds prev = vma->vm_prev; 2420146425a3SHugh Dickins /* we have start < vma->vm_end */ 24211da177e4SLinus Torvalds 24221da177e4SLinus Torvalds /* if it doesn't overlap, we have nothing.. */ 24231da177e4SLinus Torvalds end = start + len; 2424146425a3SHugh Dickins if (vma->vm_start >= end) 24251da177e4SLinus Torvalds return 0; 24261da177e4SLinus Torvalds 24271da177e4SLinus Torvalds /* 24281da177e4SLinus Torvalds * If we need to split any vma, do it now to save pain later. 24291da177e4SLinus Torvalds * 24301da177e4SLinus Torvalds * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially 24311da177e4SLinus Torvalds * unmapped vm_area_struct will remain in use: so lower split_vma 24321da177e4SLinus Torvalds * places tmp vma above, and higher split_vma places tmp vma below. 24331da177e4SLinus Torvalds */ 2434146425a3SHugh Dickins if (start > vma->vm_start) { 2435659ace58SKOSAKI Motohiro int error; 2436659ace58SKOSAKI Motohiro 2437659ace58SKOSAKI Motohiro /* 2438659ace58SKOSAKI Motohiro * Make sure that map_count on return from munmap() will 2439659ace58SKOSAKI Motohiro * not exceed its limit; but let map_count go just above 2440659ace58SKOSAKI Motohiro * its limit temporarily, to help free resources as expected. 2441659ace58SKOSAKI Motohiro */ 2442659ace58SKOSAKI Motohiro if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) 2443659ace58SKOSAKI Motohiro return -ENOMEM; 2444659ace58SKOSAKI Motohiro 2445659ace58SKOSAKI Motohiro error = __split_vma(mm, vma, start, 0); 24461da177e4SLinus Torvalds if (error) 24471da177e4SLinus Torvalds return error; 2448146425a3SHugh Dickins prev = vma; 24491da177e4SLinus Torvalds } 24501da177e4SLinus Torvalds 24511da177e4SLinus Torvalds /* Does it split the last one? */ 24521da177e4SLinus Torvalds last = find_vma(mm, end); 24531da177e4SLinus Torvalds if (last && end > last->vm_start) { 2454659ace58SKOSAKI Motohiro int error = __split_vma(mm, last, end, 1); 24551da177e4SLinus Torvalds if (error) 24561da177e4SLinus Torvalds return error; 24571da177e4SLinus Torvalds } 2458146425a3SHugh Dickins vma = prev? prev->vm_next: mm->mmap; 24591da177e4SLinus Torvalds 24601da177e4SLinus Torvalds /* 2461ba470de4SRik van Riel * unlock any mlock()ed ranges before detaching vmas 2462ba470de4SRik van Riel */ 2463ba470de4SRik van Riel if (mm->locked_vm) { 2464ba470de4SRik van Riel struct vm_area_struct *tmp = vma; 2465ba470de4SRik van Riel while (tmp && tmp->vm_start < end) { 2466ba470de4SRik van Riel if (tmp->vm_flags & VM_LOCKED) { 2467ba470de4SRik van Riel mm->locked_vm -= vma_pages(tmp); 2468ba470de4SRik van Riel munlock_vma_pages_all(tmp); 2469ba470de4SRik van Riel } 2470ba470de4SRik van Riel tmp = tmp->vm_next; 2471ba470de4SRik van Riel } 2472ba470de4SRik van Riel } 2473ba470de4SRik van Riel 2474ba470de4SRik van Riel /* 24751da177e4SLinus Torvalds * Remove the vma's, and unmap the actual pages 24761da177e4SLinus Torvalds */ 2477146425a3SHugh Dickins detach_vmas_to_be_unmapped(mm, vma, prev, end); 2478146425a3SHugh Dickins unmap_region(mm, vma, prev, start, end); 24791da177e4SLinus Torvalds 24801da177e4SLinus Torvalds /* Fix up all other VM information */ 24812c0b3814SHugh Dickins remove_vma_list(mm, vma); 24821da177e4SLinus Torvalds 24831da177e4SLinus Torvalds return 0; 24841da177e4SLinus Torvalds } 24851da177e4SLinus Torvalds 2486bfce281cSAl Viro int vm_munmap(unsigned long start, size_t len) 2487a46ef99dSLinus Torvalds { 2488a46ef99dSLinus Torvalds int ret; 2489bfce281cSAl Viro struct mm_struct *mm = current->mm; 2490a46ef99dSLinus Torvalds 2491a46ef99dSLinus Torvalds down_write(&mm->mmap_sem); 2492a46ef99dSLinus Torvalds ret = do_munmap(mm, start, len); 2493a46ef99dSLinus Torvalds up_write(&mm->mmap_sem); 2494a46ef99dSLinus Torvalds return ret; 2495a46ef99dSLinus Torvalds } 2496a46ef99dSLinus Torvalds EXPORT_SYMBOL(vm_munmap); 2497a46ef99dSLinus Torvalds 24986a6160a7SHeiko Carstens SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) 24991da177e4SLinus Torvalds { 25001da177e4SLinus Torvalds profile_munmap(addr); 2501bfce281cSAl Viro return vm_munmap(addr, len); 25021da177e4SLinus Torvalds } 25031da177e4SLinus Torvalds 25041da177e4SLinus Torvalds static inline void verify_mm_writelocked(struct mm_struct *mm) 25051da177e4SLinus Torvalds { 2506a241ec65SPaul E. McKenney #ifdef CONFIG_DEBUG_VM 25071da177e4SLinus Torvalds if (unlikely(down_read_trylock(&mm->mmap_sem))) { 25081da177e4SLinus Torvalds WARN_ON(1); 25091da177e4SLinus Torvalds up_read(&mm->mmap_sem); 25101da177e4SLinus Torvalds } 25111da177e4SLinus Torvalds #endif 25121da177e4SLinus Torvalds } 25131da177e4SLinus Torvalds 25141da177e4SLinus Torvalds /* 25151da177e4SLinus Torvalds * this is really a simplified "do_mmap". it only handles 25161da177e4SLinus Torvalds * anonymous maps. eventually we may be able to do some 25171da177e4SLinus Torvalds * brk-specific accounting here. 25181da177e4SLinus Torvalds */ 2519e4eb1ff6SLinus Torvalds static unsigned long do_brk(unsigned long addr, unsigned long len) 25201da177e4SLinus Torvalds { 25211da177e4SLinus Torvalds struct mm_struct * mm = current->mm; 25221da177e4SLinus Torvalds struct vm_area_struct * vma, * prev; 25231da177e4SLinus Torvalds unsigned long flags; 25241da177e4SLinus Torvalds struct rb_node ** rb_link, * rb_parent; 25251da177e4SLinus Torvalds pgoff_t pgoff = addr >> PAGE_SHIFT; 25263a459756SKirill Korotaev int error; 25271da177e4SLinus Torvalds 25281da177e4SLinus Torvalds len = PAGE_ALIGN(len); 25291da177e4SLinus Torvalds if (!len) 25301da177e4SLinus Torvalds return addr; 25311da177e4SLinus Torvalds 25323a459756SKirill Korotaev flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; 25333a459756SKirill Korotaev 25342c6a1016SAl Viro error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); 25352c6a1016SAl Viro if (error & ~PAGE_MASK) 25363a459756SKirill Korotaev return error; 25373a459756SKirill Korotaev 25381da177e4SLinus Torvalds /* 25391da177e4SLinus Torvalds * mlock MCL_FUTURE? 25401da177e4SLinus Torvalds */ 25411da177e4SLinus Torvalds if (mm->def_flags & VM_LOCKED) { 25421da177e4SLinus Torvalds unsigned long locked, lock_limit; 254393ea1d0aSChris Wright locked = len >> PAGE_SHIFT; 254493ea1d0aSChris Wright locked += mm->locked_vm; 254559e99e5bSJiri Slaby lock_limit = rlimit(RLIMIT_MEMLOCK); 254693ea1d0aSChris Wright lock_limit >>= PAGE_SHIFT; 25471da177e4SLinus Torvalds if (locked > lock_limit && !capable(CAP_IPC_LOCK)) 25481da177e4SLinus Torvalds return -EAGAIN; 25491da177e4SLinus Torvalds } 25501da177e4SLinus Torvalds 25511da177e4SLinus Torvalds /* 25521da177e4SLinus Torvalds * mm->mmap_sem is required to protect against another thread 25531da177e4SLinus Torvalds * changing the mappings in case we sleep. 25541da177e4SLinus Torvalds */ 25551da177e4SLinus Torvalds verify_mm_writelocked(mm); 25561da177e4SLinus Torvalds 25571da177e4SLinus Torvalds /* 25581da177e4SLinus Torvalds * Clear old maps. this also does some error checking for us 25591da177e4SLinus Torvalds */ 25601da177e4SLinus Torvalds munmap_back: 25616597d783SHugh Dickins if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { 25621da177e4SLinus Torvalds if (do_munmap(mm, addr, len)) 25631da177e4SLinus Torvalds return -ENOMEM; 25641da177e4SLinus Torvalds goto munmap_back; 25651da177e4SLinus Torvalds } 25661da177e4SLinus Torvalds 25671da177e4SLinus Torvalds /* Check against address space limits *after* clearing old maps... */ 2568119f657cSakpm@osdl.org if (!may_expand_vm(mm, len >> PAGE_SHIFT)) 25691da177e4SLinus Torvalds return -ENOMEM; 25701da177e4SLinus Torvalds 25711da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 25721da177e4SLinus Torvalds return -ENOMEM; 25731da177e4SLinus Torvalds 2574191c5424SAl Viro if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) 25751da177e4SLinus Torvalds return -ENOMEM; 25761da177e4SLinus Torvalds 25771da177e4SLinus Torvalds /* Can we just expand an old private anonymous mapping? */ 2578ba470de4SRik van Riel vma = vma_merge(mm, prev, addr, addr + len, flags, 2579ba470de4SRik van Riel NULL, NULL, pgoff, NULL); 2580ba470de4SRik van Riel if (vma) 25811da177e4SLinus Torvalds goto out; 25821da177e4SLinus Torvalds 25831da177e4SLinus Torvalds /* 25841da177e4SLinus Torvalds * create a vma struct for an anonymous mapping 25851da177e4SLinus Torvalds */ 2586c5e3b83eSPekka Enberg vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); 25871da177e4SLinus Torvalds if (!vma) { 25881da177e4SLinus Torvalds vm_unacct_memory(len >> PAGE_SHIFT); 25891da177e4SLinus Torvalds return -ENOMEM; 25901da177e4SLinus Torvalds } 25911da177e4SLinus Torvalds 25925beb4930SRik van Riel INIT_LIST_HEAD(&vma->anon_vma_chain); 25931da177e4SLinus Torvalds vma->vm_mm = mm; 25941da177e4SLinus Torvalds vma->vm_start = addr; 25951da177e4SLinus Torvalds vma->vm_end = addr + len; 25961da177e4SLinus Torvalds vma->vm_pgoff = pgoff; 25971da177e4SLinus Torvalds vma->vm_flags = flags; 25983ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(flags); 25991da177e4SLinus Torvalds vma_link(mm, vma, prev, rb_link, rb_parent); 26001da177e4SLinus Torvalds out: 26013af9e859SEric B Munson perf_event_mmap(vma); 26021da177e4SLinus Torvalds mm->total_vm += len >> PAGE_SHIFT; 26031da177e4SLinus Torvalds if (flags & VM_LOCKED) { 2604ba470de4SRik van Riel if (!mlock_vma_pages_range(vma, addr, addr + len)) 2605ba470de4SRik van Riel mm->locked_vm += (len >> PAGE_SHIFT); 26061da177e4SLinus Torvalds } 26071da177e4SLinus Torvalds return addr; 26081da177e4SLinus Torvalds } 26091da177e4SLinus Torvalds 2610e4eb1ff6SLinus Torvalds unsigned long vm_brk(unsigned long addr, unsigned long len) 2611e4eb1ff6SLinus Torvalds { 2612e4eb1ff6SLinus Torvalds struct mm_struct *mm = current->mm; 2613e4eb1ff6SLinus Torvalds unsigned long ret; 2614e4eb1ff6SLinus Torvalds 2615e4eb1ff6SLinus Torvalds down_write(&mm->mmap_sem); 2616e4eb1ff6SLinus Torvalds ret = do_brk(addr, len); 2617e4eb1ff6SLinus Torvalds up_write(&mm->mmap_sem); 2618e4eb1ff6SLinus Torvalds return ret; 2619e4eb1ff6SLinus Torvalds } 2620e4eb1ff6SLinus Torvalds EXPORT_SYMBOL(vm_brk); 26211da177e4SLinus Torvalds 26221da177e4SLinus Torvalds /* Release all mmaps. */ 26231da177e4SLinus Torvalds void exit_mmap(struct mm_struct *mm) 26241da177e4SLinus Torvalds { 2625d16dfc55SPeter Zijlstra struct mmu_gather tlb; 2626ba470de4SRik van Riel struct vm_area_struct *vma; 26271da177e4SLinus Torvalds unsigned long nr_accounted = 0; 26281da177e4SLinus Torvalds 2629d6dd61c8SJeremy Fitzhardinge /* mm's last user has gone, and its about to be pulled down */ 2630cddb8a5cSAndrea Arcangeli mmu_notifier_release(mm); 2631d6dd61c8SJeremy Fitzhardinge 2632ba470de4SRik van Riel if (mm->locked_vm) { 2633ba470de4SRik van Riel vma = mm->mmap; 2634ba470de4SRik van Riel while (vma) { 2635ba470de4SRik van Riel if (vma->vm_flags & VM_LOCKED) 2636ba470de4SRik van Riel munlock_vma_pages_all(vma); 2637ba470de4SRik van Riel vma = vma->vm_next; 2638ba470de4SRik van Riel } 2639ba470de4SRik van Riel } 26409480c53eSJeremy Fitzhardinge 26419480c53eSJeremy Fitzhardinge arch_exit_mmap(mm); 26429480c53eSJeremy Fitzhardinge 2643ba470de4SRik van Riel vma = mm->mmap; 26449480c53eSJeremy Fitzhardinge if (!vma) /* Can happen if dup_mmap() received an OOM */ 26459480c53eSJeremy Fitzhardinge return; 26469480c53eSJeremy Fitzhardinge 26471da177e4SLinus Torvalds lru_add_drain(); 26481da177e4SLinus Torvalds flush_cache_mm(mm); 2649d16dfc55SPeter Zijlstra tlb_gather_mmu(&tlb, mm, 1); 2650901608d9SOleg Nesterov /* update_hiwater_rss(mm) here? but nobody should be looking */ 2651e0da382cSHugh Dickins /* Use -1 here to ensure all VMAs in the mm are unmapped */ 26524f74d2c8SLinus Torvalds unmap_vmas(&tlb, vma, 0, -1); 26539ba69294SHugh Dickins 2654d16dfc55SPeter Zijlstra free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); 2655853f5e26SAl Viro tlb_finish_mmu(&tlb, 0, -1); 26561da177e4SLinus Torvalds 26571da177e4SLinus Torvalds /* 26588f4f8c16SHugh Dickins * Walk the list again, actually closing and freeing it, 26598f4f8c16SHugh Dickins * with preemption enabled, without holding any MM locks. 26601da177e4SLinus Torvalds */ 26614f74d2c8SLinus Torvalds while (vma) { 26624f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 26634f74d2c8SLinus Torvalds nr_accounted += vma_pages(vma); 2664a8fb5618SHugh Dickins vma = remove_vma(vma); 26654f74d2c8SLinus Torvalds } 26664f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 2667e0da382cSHugh Dickins 2668f9aed62aSHugh Dickins WARN_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); 26691da177e4SLinus Torvalds } 26701da177e4SLinus Torvalds 26711da177e4SLinus Torvalds /* Insert vm structure into process list sorted by address 26721da177e4SLinus Torvalds * and into the inode's i_mmap tree. If vm_file is non-NULL 26733d48ae45SPeter Zijlstra * then i_mmap_mutex is taken here. 26741da177e4SLinus Torvalds */ 26751da177e4SLinus Torvalds int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) 26761da177e4SLinus Torvalds { 26776597d783SHugh Dickins struct vm_area_struct *prev; 26781da177e4SLinus Torvalds struct rb_node **rb_link, *rb_parent; 26791da177e4SLinus Torvalds 26801da177e4SLinus Torvalds /* 26811da177e4SLinus Torvalds * The vm_pgoff of a purely anonymous vma should be irrelevant 26821da177e4SLinus Torvalds * until its first write fault, when page's anon_vma and index 26831da177e4SLinus Torvalds * are set. But now set the vm_pgoff it will almost certainly 26841da177e4SLinus Torvalds * end up with (unless mremap moves it elsewhere before that 26851da177e4SLinus Torvalds * first wfault), so /proc/pid/maps tells a consistent story. 26861da177e4SLinus Torvalds * 26871da177e4SLinus Torvalds * By setting it to reflect the virtual start address of the 26881da177e4SLinus Torvalds * vma, merges and splits can happen in a seamless way, just 26891da177e4SLinus Torvalds * using the existing file pgoff checks and manipulations. 26901da177e4SLinus Torvalds * Similarly in do_mmap_pgoff and in do_brk. 26911da177e4SLinus Torvalds */ 26921da177e4SLinus Torvalds if (!vma->vm_file) { 26931da177e4SLinus Torvalds BUG_ON(vma->anon_vma); 26941da177e4SLinus Torvalds vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; 26951da177e4SLinus Torvalds } 26966597d783SHugh Dickins if (find_vma_links(mm, vma->vm_start, vma->vm_end, 26976597d783SHugh Dickins &prev, &rb_link, &rb_parent)) 26981da177e4SLinus Torvalds return -ENOMEM; 26992fd4ef85SHugh Dickins if ((vma->vm_flags & VM_ACCOUNT) && 270034b4e4aaSAlan Cox security_vm_enough_memory_mm(mm, vma_pages(vma))) 27012fd4ef85SHugh Dickins return -ENOMEM; 27022b144498SSrikar Dronamraju 27031da177e4SLinus Torvalds vma_link(mm, vma, prev, rb_link, rb_parent); 27041da177e4SLinus Torvalds return 0; 27051da177e4SLinus Torvalds } 27061da177e4SLinus Torvalds 27071da177e4SLinus Torvalds /* 27081da177e4SLinus Torvalds * Copy the vma structure to a new location in the same mm, 27091da177e4SLinus Torvalds * prior to moving page table entries, to effect an mremap move. 27101da177e4SLinus Torvalds */ 27111da177e4SLinus Torvalds struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, 271238a76013SMichel Lespinasse unsigned long addr, unsigned long len, pgoff_t pgoff, 271338a76013SMichel Lespinasse bool *need_rmap_locks) 27141da177e4SLinus Torvalds { 27151da177e4SLinus Torvalds struct vm_area_struct *vma = *vmap; 27161da177e4SLinus Torvalds unsigned long vma_start = vma->vm_start; 27171da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 27181da177e4SLinus Torvalds struct vm_area_struct *new_vma, *prev; 27191da177e4SLinus Torvalds struct rb_node **rb_link, *rb_parent; 27201da177e4SLinus Torvalds struct mempolicy *pol; 2721948f017bSAndrea Arcangeli bool faulted_in_anon_vma = true; 27221da177e4SLinus Torvalds 27231da177e4SLinus Torvalds /* 27241da177e4SLinus Torvalds * If anonymous vma has not yet been faulted, update new pgoff 27251da177e4SLinus Torvalds * to match new location, to increase its chance of merging. 27261da177e4SLinus Torvalds */ 2727948f017bSAndrea Arcangeli if (unlikely(!vma->vm_file && !vma->anon_vma)) { 27281da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 2729948f017bSAndrea Arcangeli faulted_in_anon_vma = false; 2730948f017bSAndrea Arcangeli } 27311da177e4SLinus Torvalds 27326597d783SHugh Dickins if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) 27336597d783SHugh Dickins return NULL; /* should never get here */ 27341da177e4SLinus Torvalds new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, 27351da177e4SLinus Torvalds vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); 27361da177e4SLinus Torvalds if (new_vma) { 27371da177e4SLinus Torvalds /* 27381da177e4SLinus Torvalds * Source vma may have been merged into new_vma 27391da177e4SLinus Torvalds */ 2740948f017bSAndrea Arcangeli if (unlikely(vma_start >= new_vma->vm_start && 2741948f017bSAndrea Arcangeli vma_start < new_vma->vm_end)) { 2742948f017bSAndrea Arcangeli /* 2743948f017bSAndrea Arcangeli * The only way we can get a vma_merge with 2744948f017bSAndrea Arcangeli * self during an mremap is if the vma hasn't 2745948f017bSAndrea Arcangeli * been faulted in yet and we were allowed to 2746948f017bSAndrea Arcangeli * reset the dst vma->vm_pgoff to the 2747948f017bSAndrea Arcangeli * destination address of the mremap to allow 2748948f017bSAndrea Arcangeli * the merge to happen. mremap must change the 2749948f017bSAndrea Arcangeli * vm_pgoff linearity between src and dst vmas 2750948f017bSAndrea Arcangeli * (in turn preventing a vma_merge) to be 2751948f017bSAndrea Arcangeli * safe. It is only safe to keep the vm_pgoff 2752948f017bSAndrea Arcangeli * linear if there are no pages mapped yet. 2753948f017bSAndrea Arcangeli */ 2754948f017bSAndrea Arcangeli VM_BUG_ON(faulted_in_anon_vma); 275538a76013SMichel Lespinasse *vmap = vma = new_vma; 2756108d6642SMichel Lespinasse } 275738a76013SMichel Lespinasse *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); 27581da177e4SLinus Torvalds } else { 2759e94b1766SChristoph Lameter new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); 27601da177e4SLinus Torvalds if (new_vma) { 27611da177e4SLinus Torvalds *new_vma = *vma; 27621da177e4SLinus Torvalds new_vma->vm_start = addr; 27631da177e4SLinus Torvalds new_vma->vm_end = addr + len; 27641da177e4SLinus Torvalds new_vma->vm_pgoff = pgoff; 2765523d4e20SMichel Lespinasse pol = mpol_dup(vma_policy(vma)); 2766523d4e20SMichel Lespinasse if (IS_ERR(pol)) 2767523d4e20SMichel Lespinasse goto out_free_vma; 2768523d4e20SMichel Lespinasse vma_set_policy(new_vma, pol); 2769523d4e20SMichel Lespinasse INIT_LIST_HEAD(&new_vma->anon_vma_chain); 2770523d4e20SMichel Lespinasse if (anon_vma_clone(new_vma, vma)) 2771523d4e20SMichel Lespinasse goto out_free_mempol; 2772e9714acfSKonstantin Khlebnikov if (new_vma->vm_file) 27731da177e4SLinus Torvalds get_file(new_vma->vm_file); 27741da177e4SLinus Torvalds if (new_vma->vm_ops && new_vma->vm_ops->open) 27751da177e4SLinus Torvalds new_vma->vm_ops->open(new_vma); 27761da177e4SLinus Torvalds vma_link(mm, new_vma, prev, rb_link, rb_parent); 277738a76013SMichel Lespinasse *need_rmap_locks = false; 27781da177e4SLinus Torvalds } 27791da177e4SLinus Torvalds } 27801da177e4SLinus Torvalds return new_vma; 27815beb4930SRik van Riel 27825beb4930SRik van Riel out_free_mempol: 27835beb4930SRik van Riel mpol_put(pol); 27845beb4930SRik van Riel out_free_vma: 27855beb4930SRik van Riel kmem_cache_free(vm_area_cachep, new_vma); 27865beb4930SRik van Riel return NULL; 27871da177e4SLinus Torvalds } 2788119f657cSakpm@osdl.org 2789119f657cSakpm@osdl.org /* 2790119f657cSakpm@osdl.org * Return true if the calling process may expand its vm space by the passed 2791119f657cSakpm@osdl.org * number of pages 2792119f657cSakpm@osdl.org */ 2793119f657cSakpm@osdl.org int may_expand_vm(struct mm_struct *mm, unsigned long npages) 2794119f657cSakpm@osdl.org { 2795119f657cSakpm@osdl.org unsigned long cur = mm->total_vm; /* pages */ 2796119f657cSakpm@osdl.org unsigned long lim; 2797119f657cSakpm@osdl.org 279859e99e5bSJiri Slaby lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT; 2799119f657cSakpm@osdl.org 2800119f657cSakpm@osdl.org if (cur + npages > lim) 2801119f657cSakpm@osdl.org return 0; 2802119f657cSakpm@osdl.org return 1; 2803119f657cSakpm@osdl.org } 2804fa5dc22fSRoland McGrath 2805fa5dc22fSRoland McGrath 2806b1d0e4f5SNick Piggin static int special_mapping_fault(struct vm_area_struct *vma, 2807b1d0e4f5SNick Piggin struct vm_fault *vmf) 2808fa5dc22fSRoland McGrath { 2809b1d0e4f5SNick Piggin pgoff_t pgoff; 2810fa5dc22fSRoland McGrath struct page **pages; 2811fa5dc22fSRoland McGrath 2812b1d0e4f5SNick Piggin /* 2813b1d0e4f5SNick Piggin * special mappings have no vm_file, and in that case, the mm 2814b1d0e4f5SNick Piggin * uses vm_pgoff internally. So we have to subtract it from here. 2815b1d0e4f5SNick Piggin * We are allowed to do this because we are the mm; do not copy 2816b1d0e4f5SNick Piggin * this code into drivers! 2817b1d0e4f5SNick Piggin */ 2818b1d0e4f5SNick Piggin pgoff = vmf->pgoff - vma->vm_pgoff; 2819fa5dc22fSRoland McGrath 2820b1d0e4f5SNick Piggin for (pages = vma->vm_private_data; pgoff && *pages; ++pages) 2821b1d0e4f5SNick Piggin pgoff--; 2822fa5dc22fSRoland McGrath 2823fa5dc22fSRoland McGrath if (*pages) { 2824fa5dc22fSRoland McGrath struct page *page = *pages; 2825fa5dc22fSRoland McGrath get_page(page); 2826b1d0e4f5SNick Piggin vmf->page = page; 2827b1d0e4f5SNick Piggin return 0; 2828fa5dc22fSRoland McGrath } 2829fa5dc22fSRoland McGrath 2830b1d0e4f5SNick Piggin return VM_FAULT_SIGBUS; 2831fa5dc22fSRoland McGrath } 2832fa5dc22fSRoland McGrath 2833fa5dc22fSRoland McGrath /* 2834fa5dc22fSRoland McGrath * Having a close hook prevents vma merging regardless of flags. 2835fa5dc22fSRoland McGrath */ 2836fa5dc22fSRoland McGrath static void special_mapping_close(struct vm_area_struct *vma) 2837fa5dc22fSRoland McGrath { 2838fa5dc22fSRoland McGrath } 2839fa5dc22fSRoland McGrath 2840f0f37e2fSAlexey Dobriyan static const struct vm_operations_struct special_mapping_vmops = { 2841fa5dc22fSRoland McGrath .close = special_mapping_close, 2842b1d0e4f5SNick Piggin .fault = special_mapping_fault, 2843fa5dc22fSRoland McGrath }; 2844fa5dc22fSRoland McGrath 2845fa5dc22fSRoland McGrath /* 2846fa5dc22fSRoland McGrath * Called with mm->mmap_sem held for writing. 2847fa5dc22fSRoland McGrath * Insert a new vma covering the given region, with the given flags. 2848fa5dc22fSRoland McGrath * Its pages are supplied by the given array of struct page *. 2849fa5dc22fSRoland McGrath * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. 2850fa5dc22fSRoland McGrath * The region past the last page supplied will always produce SIGBUS. 2851fa5dc22fSRoland McGrath * The array pointer and the pages it points to are assumed to stay alive 2852fa5dc22fSRoland McGrath * for as long as this mapping might exist. 2853fa5dc22fSRoland McGrath */ 2854fa5dc22fSRoland McGrath int install_special_mapping(struct mm_struct *mm, 2855fa5dc22fSRoland McGrath unsigned long addr, unsigned long len, 2856fa5dc22fSRoland McGrath unsigned long vm_flags, struct page **pages) 2857fa5dc22fSRoland McGrath { 2858462e635eSTavis Ormandy int ret; 2859fa5dc22fSRoland McGrath struct vm_area_struct *vma; 2860fa5dc22fSRoland McGrath 2861fa5dc22fSRoland McGrath vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); 2862fa5dc22fSRoland McGrath if (unlikely(vma == NULL)) 2863fa5dc22fSRoland McGrath return -ENOMEM; 2864fa5dc22fSRoland McGrath 28655beb4930SRik van Riel INIT_LIST_HEAD(&vma->anon_vma_chain); 2866fa5dc22fSRoland McGrath vma->vm_mm = mm; 2867fa5dc22fSRoland McGrath vma->vm_start = addr; 2868fa5dc22fSRoland McGrath vma->vm_end = addr + len; 2869fa5dc22fSRoland McGrath 28702f98735cSNick Piggin vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND; 28713ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 2872fa5dc22fSRoland McGrath 2873fa5dc22fSRoland McGrath vma->vm_ops = &special_mapping_vmops; 2874fa5dc22fSRoland McGrath vma->vm_private_data = pages; 2875fa5dc22fSRoland McGrath 2876462e635eSTavis Ormandy ret = insert_vm_struct(mm, vma); 2877462e635eSTavis Ormandy if (ret) 2878462e635eSTavis Ormandy goto out; 2879fa5dc22fSRoland McGrath 2880fa5dc22fSRoland McGrath mm->total_vm += len >> PAGE_SHIFT; 2881fa5dc22fSRoland McGrath 2882cdd6c482SIngo Molnar perf_event_mmap(vma); 2883089dd79dSPeter Zijlstra 2884fa5dc22fSRoland McGrath return 0; 2885462e635eSTavis Ormandy 2886462e635eSTavis Ormandy out: 2887462e635eSTavis Ormandy kmem_cache_free(vm_area_cachep, vma); 2888462e635eSTavis Ormandy return ret; 2889fa5dc22fSRoland McGrath } 28907906d00cSAndrea Arcangeli 28917906d00cSAndrea Arcangeli static DEFINE_MUTEX(mm_all_locks_mutex); 28927906d00cSAndrea Arcangeli 2893454ed842SPeter Zijlstra static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) 28947906d00cSAndrea Arcangeli { 2895bf181b9fSMichel Lespinasse if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { 28967906d00cSAndrea Arcangeli /* 28977906d00cSAndrea Arcangeli * The LSB of head.next can't change from under us 28987906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 28997906d00cSAndrea Arcangeli */ 2900572043c9SJiri Kosina down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem); 29017906d00cSAndrea Arcangeli /* 29027906d00cSAndrea Arcangeli * We can safely modify head.next after taking the 29035a505085SIngo Molnar * anon_vma->root->rwsem. If some other vma in this mm shares 29047906d00cSAndrea Arcangeli * the same anon_vma we won't take it again. 29057906d00cSAndrea Arcangeli * 29067906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 29077906d00cSAndrea Arcangeli * can't change from under us thanks to the 29085a505085SIngo Molnar * anon_vma->root->rwsem. 29097906d00cSAndrea Arcangeli */ 29107906d00cSAndrea Arcangeli if (__test_and_set_bit(0, (unsigned long *) 2911bf181b9fSMichel Lespinasse &anon_vma->root->rb_root.rb_node)) 29127906d00cSAndrea Arcangeli BUG(); 29137906d00cSAndrea Arcangeli } 29147906d00cSAndrea Arcangeli } 29157906d00cSAndrea Arcangeli 2916454ed842SPeter Zijlstra static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) 29177906d00cSAndrea Arcangeli { 29187906d00cSAndrea Arcangeli if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 29197906d00cSAndrea Arcangeli /* 29207906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change from under us because 29217906d00cSAndrea Arcangeli * we hold the mm_all_locks_mutex. 29227906d00cSAndrea Arcangeli * 29237906d00cSAndrea Arcangeli * Operations on ->flags have to be atomic because 29247906d00cSAndrea Arcangeli * even if AS_MM_ALL_LOCKS is stable thanks to the 29257906d00cSAndrea Arcangeli * mm_all_locks_mutex, there may be other cpus 29267906d00cSAndrea Arcangeli * changing other bitflags in parallel to us. 29277906d00cSAndrea Arcangeli */ 29287906d00cSAndrea Arcangeli if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) 29297906d00cSAndrea Arcangeli BUG(); 29303d48ae45SPeter Zijlstra mutex_lock_nest_lock(&mapping->i_mmap_mutex, &mm->mmap_sem); 29317906d00cSAndrea Arcangeli } 29327906d00cSAndrea Arcangeli } 29337906d00cSAndrea Arcangeli 29347906d00cSAndrea Arcangeli /* 29357906d00cSAndrea Arcangeli * This operation locks against the VM for all pte/vma/mm related 29367906d00cSAndrea Arcangeli * operations that could ever happen on a certain mm. This includes 29377906d00cSAndrea Arcangeli * vmtruncate, try_to_unmap, and all page faults. 29387906d00cSAndrea Arcangeli * 29397906d00cSAndrea Arcangeli * The caller must take the mmap_sem in write mode before calling 29407906d00cSAndrea Arcangeli * mm_take_all_locks(). The caller isn't allowed to release the 29417906d00cSAndrea Arcangeli * mmap_sem until mm_drop_all_locks() returns. 29427906d00cSAndrea Arcangeli * 29437906d00cSAndrea Arcangeli * mmap_sem in write mode is required in order to block all operations 29447906d00cSAndrea Arcangeli * that could modify pagetables and free pages without need of 29457906d00cSAndrea Arcangeli * altering the vma layout (for example populate_range() with 29467906d00cSAndrea Arcangeli * nonlinear vmas). It's also needed in write mode to avoid new 29477906d00cSAndrea Arcangeli * anon_vmas to be associated with existing vmas. 29487906d00cSAndrea Arcangeli * 29497906d00cSAndrea Arcangeli * A single task can't take more than one mm_take_all_locks() in a row 29507906d00cSAndrea Arcangeli * or it would deadlock. 29517906d00cSAndrea Arcangeli * 2952bf181b9fSMichel Lespinasse * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in 29537906d00cSAndrea Arcangeli * mapping->flags avoid to take the same lock twice, if more than one 29547906d00cSAndrea Arcangeli * vma in this mm is backed by the same anon_vma or address_space. 29557906d00cSAndrea Arcangeli * 29567906d00cSAndrea Arcangeli * We can take all the locks in random order because the VM code 2957631b0cfdSYuanhan Liu * taking i_mmap_mutex or anon_vma->rwsem outside the mmap_sem never 29587906d00cSAndrea Arcangeli * takes more than one of them in a row. Secondly we're protected 29597906d00cSAndrea Arcangeli * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex. 29607906d00cSAndrea Arcangeli * 29617906d00cSAndrea Arcangeli * mm_take_all_locks() and mm_drop_all_locks are expensive operations 29627906d00cSAndrea Arcangeli * that may have to take thousand of locks. 29637906d00cSAndrea Arcangeli * 29647906d00cSAndrea Arcangeli * mm_take_all_locks() can fail if it's interrupted by signals. 29657906d00cSAndrea Arcangeli */ 29667906d00cSAndrea Arcangeli int mm_take_all_locks(struct mm_struct *mm) 29677906d00cSAndrea Arcangeli { 29687906d00cSAndrea Arcangeli struct vm_area_struct *vma; 29695beb4930SRik van Riel struct anon_vma_chain *avc; 29707906d00cSAndrea Arcangeli 29717906d00cSAndrea Arcangeli BUG_ON(down_read_trylock(&mm->mmap_sem)); 29727906d00cSAndrea Arcangeli 29737906d00cSAndrea Arcangeli mutex_lock(&mm_all_locks_mutex); 29747906d00cSAndrea Arcangeli 29757906d00cSAndrea Arcangeli for (vma = mm->mmap; vma; vma = vma->vm_next) { 29767906d00cSAndrea Arcangeli if (signal_pending(current)) 29777906d00cSAndrea Arcangeli goto out_unlock; 29787906d00cSAndrea Arcangeli if (vma->vm_file && vma->vm_file->f_mapping) 2979454ed842SPeter Zijlstra vm_lock_mapping(mm, vma->vm_file->f_mapping); 29807906d00cSAndrea Arcangeli } 29817cd5a02fSPeter Zijlstra 29827cd5a02fSPeter Zijlstra for (vma = mm->mmap; vma; vma = vma->vm_next) { 29837cd5a02fSPeter Zijlstra if (signal_pending(current)) 29847cd5a02fSPeter Zijlstra goto out_unlock; 29857cd5a02fSPeter Zijlstra if (vma->anon_vma) 29865beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 29875beb4930SRik van Riel vm_lock_anon_vma(mm, avc->anon_vma); 29887cd5a02fSPeter Zijlstra } 29897cd5a02fSPeter Zijlstra 2990584cff54SKautuk Consul return 0; 29917906d00cSAndrea Arcangeli 29927906d00cSAndrea Arcangeli out_unlock: 29937906d00cSAndrea Arcangeli mm_drop_all_locks(mm); 2994584cff54SKautuk Consul return -EINTR; 29957906d00cSAndrea Arcangeli } 29967906d00cSAndrea Arcangeli 29977906d00cSAndrea Arcangeli static void vm_unlock_anon_vma(struct anon_vma *anon_vma) 29987906d00cSAndrea Arcangeli { 2999bf181b9fSMichel Lespinasse if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { 30007906d00cSAndrea Arcangeli /* 30017906d00cSAndrea Arcangeli * The LSB of head.next can't change to 0 from under 30027906d00cSAndrea Arcangeli * us because we hold the mm_all_locks_mutex. 30037906d00cSAndrea Arcangeli * 30047906d00cSAndrea Arcangeli * We must however clear the bitflag before unlocking 3005bf181b9fSMichel Lespinasse * the vma so the users using the anon_vma->rb_root will 30067906d00cSAndrea Arcangeli * never see our bitflag. 30077906d00cSAndrea Arcangeli * 30087906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 30097906d00cSAndrea Arcangeli * can't change from under us until we release the 30105a505085SIngo Molnar * anon_vma->root->rwsem. 30117906d00cSAndrea Arcangeli */ 30127906d00cSAndrea Arcangeli if (!__test_and_clear_bit(0, (unsigned long *) 3013bf181b9fSMichel Lespinasse &anon_vma->root->rb_root.rb_node)) 30147906d00cSAndrea Arcangeli BUG(); 3015cba48b98SRik van Riel anon_vma_unlock(anon_vma); 30167906d00cSAndrea Arcangeli } 30177906d00cSAndrea Arcangeli } 30187906d00cSAndrea Arcangeli 30197906d00cSAndrea Arcangeli static void vm_unlock_mapping(struct address_space *mapping) 30207906d00cSAndrea Arcangeli { 30217906d00cSAndrea Arcangeli if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 30227906d00cSAndrea Arcangeli /* 30237906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change to 0 from under us 30247906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 30257906d00cSAndrea Arcangeli */ 30263d48ae45SPeter Zijlstra mutex_unlock(&mapping->i_mmap_mutex); 30277906d00cSAndrea Arcangeli if (!test_and_clear_bit(AS_MM_ALL_LOCKS, 30287906d00cSAndrea Arcangeli &mapping->flags)) 30297906d00cSAndrea Arcangeli BUG(); 30307906d00cSAndrea Arcangeli } 30317906d00cSAndrea Arcangeli } 30327906d00cSAndrea Arcangeli 30337906d00cSAndrea Arcangeli /* 30347906d00cSAndrea Arcangeli * The mmap_sem cannot be released by the caller until 30357906d00cSAndrea Arcangeli * mm_drop_all_locks() returns. 30367906d00cSAndrea Arcangeli */ 30377906d00cSAndrea Arcangeli void mm_drop_all_locks(struct mm_struct *mm) 30387906d00cSAndrea Arcangeli { 30397906d00cSAndrea Arcangeli struct vm_area_struct *vma; 30405beb4930SRik van Riel struct anon_vma_chain *avc; 30417906d00cSAndrea Arcangeli 30427906d00cSAndrea Arcangeli BUG_ON(down_read_trylock(&mm->mmap_sem)); 30437906d00cSAndrea Arcangeli BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); 30447906d00cSAndrea Arcangeli 30457906d00cSAndrea Arcangeli for (vma = mm->mmap; vma; vma = vma->vm_next) { 30467906d00cSAndrea Arcangeli if (vma->anon_vma) 30475beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 30485beb4930SRik van Riel vm_unlock_anon_vma(avc->anon_vma); 30497906d00cSAndrea Arcangeli if (vma->vm_file && vma->vm_file->f_mapping) 30507906d00cSAndrea Arcangeli vm_unlock_mapping(vma->vm_file->f_mapping); 30517906d00cSAndrea Arcangeli } 30527906d00cSAndrea Arcangeli 30537906d00cSAndrea Arcangeli mutex_unlock(&mm_all_locks_mutex); 30547906d00cSAndrea Arcangeli } 30558feae131SDavid Howells 30568feae131SDavid Howells /* 30578feae131SDavid Howells * initialise the VMA slab 30588feae131SDavid Howells */ 30598feae131SDavid Howells void __init mmap_init(void) 30608feae131SDavid Howells { 306100a62ce9SKOSAKI Motohiro int ret; 306200a62ce9SKOSAKI Motohiro 306300a62ce9SKOSAKI Motohiro ret = percpu_counter_init(&vm_committed_as, 0); 306400a62ce9SKOSAKI Motohiro VM_BUG_ON(ret); 30658feae131SDavid Howells } 3066